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Virtual Disk API Programming Guide

1. VixDiskLib_ConnectEx amp connectParams TRUE NULL NULL amp connection diskHandles GetMyDiskHandles diskPaths connection amp connectParams flags amp numberOfDisks vixError VIX_ERR_CODE VixMntapi_OpenDiskSet diskHandles numberOfDisks flags amp diskSet GetOsInfo diskSet vixError VIX_ERR_CODE VixMntapi_GetVoLumeHandles diskSet amp numberOfVoLumes amp voLumeHandles for size_t i 0 i lt numberOfVoLlumes i VixVoLumeHandLle voLumeHandle voLlumeHandles i VixVoLumeInfo voLumeInfo vixError VIX_ERR_CODEC VixMntapi_MountVoLume voLlumeHandle TRUE vixError VIX_ERR_CODEC VixMntapi_GetVoLumeInfo volumeHandle amp volumeInfo VixMntapi_FreeVoLumeInfo volumelInfo VerifyMountedVoLume CleanUpMountedVoLume voLlumeHandle volumelInfo VixMntapi_FreeVolumeHandles volumeHandles vixError VIX_ERR_CODE C VixMntapi_CloseDiskSet diskSet FreeMyDiskHandles diskHandles numberOfDisks VixMntapi_ExitQ VixDiskLib_ExitQ Restrictions on Virtual Disk Mount The following limitations apply when mounting virtual disks VMware Inc You cannot mount virtual disks that are in use by a running or suspended virtual machine You can mount disks from a powered off virtual machine disks not associated with a virtual machine or base disks when a Windows virtual machine is running off a snapshot read only You can mount the last snapshot in a chain read write but you must mount p
2. Console WriteLine Provider vDC Name providerVdcRef name foreach string morefitem in VMWProviderVdc GetResourcePooLsByMoref client providerVdcRef Keys Console WriteLine Moref morefitem foreach VMWProviderVdcResourcePoolType VcResourcePool in VMWProviderVdc GetResourcePooLsByMoref client providerVdcRef Values string VcResourcePoollId GetId VcResourcePool ResourcePooLVim0bjectRef VimServerRef href Console WriteLine VcResourcePoolId VcResourcePoolld foreach ReferenceType item in GetDataStore VMware Inc 95 Virtual Disk Programming Guide 96 string DatastoreId GetId item href Console WriteLine Data Store ID Datastoreld Console WriteLine DataStore item name Retrieving Catalog information Catalogs on vCloud Director store vApp templates and ISO images as Catalog items Backup solutions can be asked to back up the items in the Catalog for a given Organization Catalogs can be shared or private A user can choose to back up all items or only selected items in the given catalog For this it is necessary to traverse the given Catalog in an Organization to access the contents and extract the various metadata associated with the vApp Example 8 8 shows inventory traversal to access the Catalog items in a given Organization and assumes you have already logged in to vCloud Director and obtained a map of Organizations as in Example 8 1 Example 8 8 List Ca
3. disk2 setKey 100 disk2 setControllerKey new Integer 44 disk2 setUnitNumber new Integer 1 disk2 setBacking diskfileBacking2 disk2 setCapacityInKB 131072 deviceConfigSpec 3 setDevice disk2 Finally formulate the NIC deviceConfigSpec 4 setOperation VirtualDeviceConfigSpecOperation add com VMware vim VirtualEthernetCard nic new VirtualPCNet32 VirtuaLEthernetCardNetworkBackingInfo nicBacking new VirtualEthernetCardNetworkBackingInfoQ nicBacking setNetwork networkRef nicBacking setDeviceName networkName nic setAddressType generated nic setBacking nicBacking nic setKey 48 deviceConfigSpec 4 setDevice nic Now that it is all put together create the virtual machine Note that folderMo resourcePool and hostMo are moRefs to the Folder ResourcePool and Host where the VM is to be created ManagedObjectReference taskMoRef serviceConnection getService createVM_Task folderMo configSpec resourcePool hostMo Using the VirtualMachineConfigInfo A backup application can also use information contained in a VirtualMachineConfigInfo If at backup time you preserve all the VirtualMachineConfigInfo details that describe the virtual machine you can transfer much of this information into a VirtualMachineConfigSpec to create a virtual machine at restore time However some of the information in VirtualMachineConfigInfo is not needed and if used in the Spec virtual machine creat
4. The data returned from CheckForUpdates or WaitForUpdates is an array of PropertyFilterUpdate entries Since a PropertyFilterUpdate entry is very generic here is some code showing how to extract information from the PropertyFilterUpdate Extract the PropertyFilterUpdate set from the changeData PropertyFilterUpdate updateSet changeData getFilterSetQ There is one entry in the updateSet for each filter you registered with the PropertyCollector Since we currently have only one filter the array length should be one PropertyFilterUpdate myUpdate updateSet 0 ObjectUpdate changes myUpdate getObjectSet for a 0 a lt changes length a ObjectUpdate theObject changes a String objName theObject getObj getMoType getName Must decide how to handle the value based on the name returned The only names returned are names found in the PropertySpec lists Get propertyName and value J Getting Specific Data From time to time you might need to get data that is relevant to a single item In that case you can create a simple ObjectSpec including the moRef for the item of interest The PropertySpec can then be set to obtain the properties you want and you can use RetrieveProperties to get the data Hopefully you can deduce moRef from a general examination of the properties by searching for information from the rootFolder Identifying Virtual Disks for Backup and Restore To back up a virtual m
5. on page 81 Best Practices for NBDSSL Transport Various versions of ESX ESXi have different defaults for timeouts Before ESXi 5 0 there were no default network file copy NFC timeouts Default NFC timeout values may change in future releases VMware recommends that you specify default NFC timeouts in the VixDiskLib configuration file If you do not specify a timeout older versions of ESX ESXi hold the corresponding disk open indefinitely until vpxa or hostd is restarted However if you do specify a timeout you might need to perform some keepalive operation to prevent the disk from being closed on the server side Reading block 0 periodically is a good keepalive operation As a starting point recommended settings are three minutes for Accept and Request one minute for Read ten minutes for Write and no timeouts 0 for nfcFssrvr and nfcFssrvrwrite VMware Inc Designing vSphere Backup Solutions General Backup and Restore For incremental backup of virtual disk always enable changed block tracking CBT before the first snapshot When doing full restores of virtual disk disable CBT for the duration of the restore File based restores affect change tracking but disabling CBT is optional for partial restore file level restore except with SAN transport CBT should be disabled for SAN transport writes because the file system must be able to account for thin disk allocation and clear lazy zero operations during SAN writes B
6. vim vm device VirtualLsiLogicController dynamicType lt unset gt key number of SCSI controller key 44 deviceInfo vim Description null backing vim vm device VirtualDevice BackingInfo null connectable vim vm device VirtualDevice ConnectInfo null controllerKey lt unset gt unitNumber lt unset gt busNumber 0 hotAddRemove lt unset gt sharedBus noSharing scsiCtLrUnitNumber lt unset gt Fa Cvim vm device VirtualDeviceSpec VMware Inc 75 Virtual Disk Programming Guide dynamicType lt unset gt operation add fileOperation lt unset gt Network controller device vim vm device VirtuaLPCNet32 dynamicType lt unset gt key number of Network controller key 48 deviceInfo vim Description null backing vim vm device VirtualEthernetCard NetworkBackingInfo dynamicType lt unset gt deviceName Virtual Machine Network useAutoDetect lt unset gt network lt unset gt inPassthroughMode lt unset gt connectable vim vm device VirtuaLDevice ConnectInfo dynamicType lt unset gt startConnected true allowGuestControl true connected true Js controllerKey lt unset gt unitNumber lt unset gt addressType generated macAddress lt unset gt wakeOnLanEnabled true vim vm device VirtualDeviceSpec dynamicType lt unset gt operation add fileOperat
7. About the HotAdd Proxy on page 25 so that the proxy can back up very large virtual disks A redo log is created for HotAdded disks on the same datastore as the base disks Do not remove the target virtual machine the one being backed up while HotAdded disk is still attached If removed HotAdd fails to properly clean up redo logs so virtual disks must be removed manually from the backup appliance Also do not remove the snapshot until after cleanup Removing it could result in an unconsolidated redo log HotAdd is a SCSI feature and does not work for IDE disks The paravirtual SCSI controller PVSCSIJ is not supported for HotAdd use the LSI controller instead Removing all disks on a controller with the vSphere Client also removes the controller You might want to include some checks in your code to detect this in your appliance and reconfigure to add controllers back in Virtual disk created on Windows by HotAdd backup or restore might have a different disk signature than the original virtual disk The workaround is to reread or rewrite the first disk sector in NBD mode HotAdded disks should be released with VixDiskLib_Cleanup before snapshot delete Cleanup might cause improper removal of the change tracking ctk file You can fix it by power cycling the virtual machine Customers running a Windows Server 2008 proxy on SAN storage should set SAN policy to onlineAll see note about SAN policy in Best Practices for SAN Transport
8. vixError VixDiskLib_PrepareForAccess amp cnxParams Sample if vixError VIX_OK break else Sleep 60000 38 VMware Inc Virtual Disk API Functions SAN Mode on Linux Uses Direct Mode With SAN transport on Linux read and write operations are performed in direct mode O_DIRECT meaning that no read or write buffering is done Direct mode prevents other processes from accessing the latest data and avoids loss of information if the process dies before committing its write buffers In direct mode the most time efficient performance can be achieved if applications follow these guidelines when performing reads and writes m The offset into the SAN where the operation is performed should be an even multiple of page size 4096 m The buffer used for data transfer should be aligned on a page boundary m The transfer length should be an even multiple of the page size Clean Up After Disconnect If virtual machine state was not cleaned up correctly after connection shut down VixDiskLib_Cleanup removes extra state for each virtual machine Its three parameters specify connection and pass back the number of virtual machines cleaned up and the number remaining to be cleaned up int numCleanedUp numRemaining VixError vixError VixDiskLib_Cleanup amp cnxParams amp numCleanedUp amp numRemaining Updating Applications for Advanced Transport To update your applications for advanced transport with man
9. Backing Up vApps in vCloud Director Example 8 9 shows the REST API calls that accomplish some of the tasks shown in Example 8 8 Example 8 9 REST API Calls To List Catalog Items GET https vCloud api catalog id GET https vCloud api catalog id catalogItems GET https vCloud api catalogitem id Retrieving vApp Configuration For a typical user a vApp is the basic unit of backup specified in vCloud Director The current generation of backup software maps vApps to their associated virtual machines in vSphere and thus the virtual machine becomes an actual artifact Virtual disk and virtual machine configuration files need to be stored in a backup Along with the associated virtual machine artifacts the user needs to back up the metadata and properties associated with every vApp to successfully restore it in vCloud Director when needed When a vApp is lost or deleted from vCloud Director backup software can restore the vApp by composing a new vApp using virtual machines restored in vSphere In such a case it becomes imperative to restore the properties and metadata associated with the vApp in vCloud Director The SDK includes a number of methods that you can use to get vApp configuration information Although some of this information is included in the OVF used to upload the vApp to vCloud Director the information might have subsequently been modified either by using the vCloud API or through the user interface All of these methods
10. can be modified with a zero filled 6 digit decimal sequence number to ensure that the vmdk files are uniquely named Depending on whether or not the current virtual machine had a pre existing snapshot the disk name for a snapshot could have this format lt diskname gt lt NNNNNN gt vmdk This unique name is no longer valid after the snapshot is destroyed so any data for a snapshot disk should be stored in the backup program under its base disk name The following code sample shows how to create a snapshot on a specific virtual machine At this point we assume the virtual machine is identified as ManagedObjectReference vmMoRef String SnapshotName Backup String SnapshotDescription Temporary Snapshot for Backup boolean memory_files false boolean quiesce_filesystem true ManagedObjectReference taskRef serviceConnection getservice CreateSnapshot_Task vmMoRef SnapshotName SnapshotDescription memory_files quiesce_filesystem You can use the taskRef return value as a moRef to track progress of the snapshot operation After successful completion taskRef info result contains the moRef of the snapshot Backing Up a Virtual Disk This section describes how to get data from the Virtual Disk after you have identified it In order to access a virtual disk you must use the VixDiskLib The following code shows how to initialize the VixDiskLib and use it for accessing a virtual disk All operations require a VixDiskL
11. or the ISO9660 file system for writing files on CD or NFS version 2 or Linux kernel 2 4 All are limited to 2GB per volume FAT and FAT32 were extended to 4GB in NT 3 51 However a SPLIT virtual disk might be safer than the MONOLITHIC variety because if something goes wrong with the underlying host file system some data might be recoverable from uncorrupted 2GB extents VMware products do their best to repair a damaged VMDK but having a split VMDK increases the chance of salvaging files during repair On the downside SPLIT virtual disk involves higher overhead more file descriptors and increases administrative complexity When required for a FAT16 or early Linux file system you can create SPLIT_SPARSE virtual disk The change is simple the line highlighted in boldface The sample program could be extended to have an option for this static void DoCreate void VixDiskLibAdapterType adapter strcmp appGlobals adapterType scsi 0 VIXDISKLIB_ADAPTER_SCSI_BUSLOGIC VIXDISKLIB_ADAPTER_IDE VixDiskLibCreateParams createParams VixError vixError createParams adapterType adapter createParams capacity appGlobals mbSize 2048 createParams diskType VIXDISKLIB_DISK_SPLIT_SPARSE vixError VixDiskLib_Create appGlobals connection appGlobals diskPath amp createParams NULL NULL CHECK_AND_THROW vixError NOTE You can split VMDK files into smaller than 2GB extents but created filenames still follow the patterns s
12. or when any parent or child in the chain needs disk consolidation or is in a bad snapshot state it is possible to have extra too many parent backing objects Consequently restore applications should never assume the correct number of parent backing objects They must recursively query until the base parent backing object is reached and make sure when restoring leaf nodes that the correct parent backing object matches the node being restored Administrative Disk Operations 34 These functions rename grow defragment shrink and remove virtual disk Rename an Existing Disk VixDiskLib_Rename changes the name of a virtual disk Use this function only when the virtual machine is powered off vixError VixDiskLib_Rename oldGlobals diskPath newGlobals diskPath Grow an Existing Local Disk VixDiskLib_Grow extends an existing virtual disk by adding sectors This function supports hosted disk but not managed disk vixError VixDiskLib_Grow appGlobals connection appGlobals diskPath size FALSE GrowProgressFunc NULL Defragment an Existing Disk VixDiskLib_Defragment defragments an existing virtual disk Defragmentation is effective with SPARSE type files but might not do anything with FLAT type In either case the function returns VIX_OK This function supports hosted disk but not managed disk vixError VixDiskLib_Defragment disk Handle DefragProgressFunc NULL Defragment consolidates data in the 2GB ex
13. 12 Backup Design for vCloud Director 12 Use Cases for the Virtual Disk Library 12 Developing for VMware Platform Products 12 Managed Disk and Hosted Disk 13 Advanced Transports 14 VDDK and VADP Compared 14 Platform Product Compatibility 14 Redistributing VDDK Components 14 2 Installing the Development Kit 15 Prerequisites 15 Development Systems 15 Programming Environments 15 Visual Studio on Windows 15 C and C on Linux 15 Java Development for VADP 15 VMware Platform Products 15 Storage Device Support 16 Installing the VDDK Package 16 Repackaging VDDK Libraries 17 How to Find VADP Components 17 3 Virtual Disk Interfaces 19 VMDK File Location 19 Virtual Disk Types 19 Persistence Disk Modes 20 VMDK File Naming 20 Thin Provisioned Disk 21 Internationalization and Localization 21 Virtual Disk Internal Format 21 Grain Directories and Grain Tables 21 Data Structures in Virtual Disk API 21 Credentials and Privileges for VMDK Access 22 Adapter Types 23 Virtual Disk Transport Methods 23 Local File Access 23 SAN Transport 23 HotAdd Transport 24 VMware Inc Virtual Disk Programming Guide About the HotAdd Proxy 25 NBD and NBDSSL Transport 25 SSL Certificates and Security 26 NEC Session Limits 26 4 Virtual Disk API Functions 27 Virtual Disk Library Functions 27 Alphabetic Table of Functions 28 Start Up 28 Initialize the Library 29 Connect to a Workstation or Server 29 VMX Specification 29 Disk Operations 30 Create a New
14. 4b9a 9dOd 588629e63347 gt lt vmext MoRef gt datastore 29 lt vmext MoRef gt lt vmext VimObjectType gt DATASTORE lt vmext VimObjectType gt lt vmext DatastoreVimObjectRef gt lt vmext HostVimObjectRef gt lt vmext VimServerRef type appLlication vnd vmware admin vmwvirtualcenter xmL name dao_w2k8_vc href https 10 20 140 167 api admin extension vimServer e7026985 19fF6 4b9a 9dOd 588629e63347 gt lt vmext MoRef gt host 28 lt vmext MoRef gt lt vmext Vim0bjectType gt HOST lt vmext VimObjectType gt lt vmext HostVimObjectRef gt lt vmext VirtualLDisksMaxChainLength gt 1 lt vmext Virtua lLDisksMaxChainLength gt lt vmext VmVimInfo gt lt VCloudExtension gt lt Vm gt Besides the virtual machine object itself the VmVIMInfo element encapsulated in the VCloudExtension element of Example 8 14 lists a datastore object and a host object Each section provides the vSphere entity reference MoRef for the corresponding entity along with its type The types are DATASTORE and HOST respectively In vCloud Director the virtual machine can be described as virtual machine vm 63 stored in datastore datastore 29 and managed by vCenter Server dao_w2k8_vc In a similar way Example 8 15 shows the administrative view of a VDC wherein the VCloudExtension element provides additional information about the corresponding entities in vSphere In this particular case the VDC in the example is base
15. Afterwards the base disk contains a redo of all changes that the virtual machine made while the snapshot was active Create Child from Parent Disk Usually you create the first child disk from the parent and create successive children from the latest one in the chain The disk tracks in SPARSE format any disk sectors changed since inception as illustrated in Figure 4 1 Figure 4 1 Child Disks Created from Parent Virtual Machine Writes Here v Child3 vm vmdk vm 001 vmdk Changed Sectors Only vy Child2 vm vmdk vm 002 vmdk Child1 vm vmdk vm 001 vmdk y Parent vm vmdk vm flat vmdk Physical Disk 32 VMware Inc Virtual Disk API Functions VixDiskLib_CreateChild creates a child disk or redo log for a hosted virtual disk After you create a child it is generally not necessary to open the parent or earlier children in the disk chain The children s vm vmdk files point to redo logs not to the parent disk vm f Lat vmdk in this example To access the original parent or earlier children in the chain you can use VixDiskLib_Attach on hosted disk vixError VixDiskLib_CreateChild parent Handle Q appGlobals diskPath VIXDISKLIB_DISK_MONOLITHIC_SPARSE NULL NULL Attach Child to Parent Disk VixDiskLib_Attach attaches the child disk into its parent disk chain Afterwards the parent handle is inv
16. Boolean true tools setBeforeGuestShutdown new Boolean true tools setBeforeGuestReboot new Boolean true Set flags VirtualMachineFlagInfo flags new VirtualMachineFlagInfoQ configSpec setFlags flags flags setSnapshotPower0ffBehavior powerOfFf Set power op info VirtualMachineDefaultPowerOpInfo powerInfo new VirtualMachineDefaultPowerOpInfo configSpec setPowerOpInfo powerInfo powerInfo setPowerOffType preset powerInfo setSuspendType preset powerInfo setResetType preset powerInfo setStandbyAction powerOnSuspend Now add in the devices VirtualDeviceConfigSpec deviceConfigSpec new VirtualDeviceConfigSpec 5 configSpec setDeviceChange deviceConfigSpec Formulate the CDROM deviceConfigSpec 0 setOperation VirtualDeviceConfigSpecOperation add VirtuaLCdrom cdrom new VirtualCdromQ VirtualCdromIsoBackingInfo cdDeviceBacking new VirtualCdromRemotePassthroughBackingInfo cdDeviceBacking setDatastore datastoreRef cdrom setBacking cdDeviceBacking cdrom setKey 42 cdrom setControllerKey new Integer 200 Older Java required type for optional properties cdrom setUnitNumber new Integer 0 deviceConfigSpec 0 setDevice cdrom Formulate the SCSI controller deviceConfigSpec 1 setOperation VirtualDeviceConfigSpecOperation add VirtuaLLsiLogicController scsiCtrl new VirtualLsiLogicControllerQ scsiCtr1l setBusNumber 0 deviceConf
17. Components on page 11 m Use Cases for the Virtual Disk Library on page 12 m Developing for VMware Platform Products on page 12 The virtual disk development kit VDDK is an SDK to help developers create applications that access storage on virtual machines The VDDK package is based on the virtual disk API introduced in this chapter The VMware Storage APIs Data Protection VADP use the virtual disk API and a subset of vSphere APIs to take snapshots of virtual machines running on ESXi enabling full or incremental backup and restore VADP replaces VMware Consolidated Backup VCB About the Virtual Disk API The virtual disk API or VixDiskLib is a set of function calls to manipulate virtual disk files in VMDK format virtual machine disk Function call semantics are patterned after C system calls for file I O Using the virtual disk API you can write programs to manage VMDK files directly from your software applications These library functions can manipulate virtual disks on VMware Workstation or similar products hosted disk or virtual disks residing on VMFS volumes of an ESX ESXi host managed disk Hosted is a term indicating that the virtualization platform is hosted by a guest operating system such as Windows or Linux The VDDK package installs on either Windows or Linux so you can write VDDK and VADP applications using either system Applications can manipulate the virtual disks of any operating system that runs
18. GET https vCloud api vapp id leaseSettingsSection GET https vCloud api vapp id owner GET https vCloud api vapp id metadata Virtual Machine Information vCloud Director also stores virtual machine configuration information uploaded from an OVF file into a vApp template If you have not modified a virtual machine configuration since uploading you can use this information to verify the configuration of the virtual machine before restoring it The following methods applied to an object of type VM retrieve configuration data structures from vCloud Director Configuration Data for a Virtual Machine m GetVirtualHardwareSection Get hardware requirements of the virtual machine Returns VirtualhardwareSection_Type m GetOperatingSystemSection Get information about the guest operating system installed on this virtual machine Returns OperatingSystemSectionType m GetNetworkConnectionSection Get information about virtual network devices used by this virtual machine Returns NetworkConnectionSectionType m GetRuntimeInfoSection Get version of VMware Tools installed on the virtual machine Returns RuntimeInfoSectionType Example 8 11 shows the REST API calls corresponding to the virtual machine configuration sections available from the SDK for NET Example 8 11 REST API Calls To Get Virtual Machine Configuration Data GET https vCloud api vapp id virtualhardwaresection GET https vCloud api vapp id operatingSystem
19. Guest Operating Systems Guest Operating System Driver Type Used Quiescing Type Used Windows XP 32 bit Sync Driver File system consistent quiescing Windows 2000 32 bit Windows Vista 32 or 64 bit VMware VSS component File system consistent quiescing Windows 7 32 or 64 bit Windows 2003 32 or 64 bit VMware VSS component Application consistent quiescing Windows 2008 32 or 64 bit VMware VSS component Application consistent quiescing For Windows Server 2008 R2 application consistent quiescing to be available several conditions must be met m Virtual machine must be running on ESXi 4 1 or later m The UUID attribute must be enabled It is enabled by default for virtual machines created on 4 1 or later For details about enabling this attribute see Enable Windows 2008 Virtual Machine Application Consistent Quiescing on page 85 m The virtual machine must use SCSI disks only and have as many free SCSI slots as the number of disks Application consistent quiescing is not supported for virtual machines with IDE disks m The virtual machine must not use dynamic disks Windows Server 2012 VMware VSS component Same as above Other guest operating system Not applicable Crash consistent quiescing Restore must be done using the backup application s guest agent The vSphere APIs for Data Protection provide no host agent support for this Applications authenticating with SSPI might not work right because HTTP access will de
20. Hosted Disk 30 Open a Local or Remote Disk 30 Read Sectors From a Disk 30 Write Sectors To a Disk 30 Close a Local or Remote Disk 30 Get Information About a Disk 30 Free Memory from Get Information 31 Error Handling 31 Return Error Description Text 31 Free Error Description Text 31 Metadata Handling 31 Read Metadata Key from Disk 31 Get Metadata Table from Disk 31 Write Metadata Table to Disk 31 Cloning a Virtual Disk 31 Compute Space Needed for Clone 31 Clone a Disk by Copying Data 32 Disk Chaining and Redo Logs 32 Create Child from Parent Disk 32 Attach Child to Parent Disk 33 Opening ina Chain 33 Redo Logs and Linked Clone Backup 34 Administrative Disk Operations 34 Rename an Existing Disk 34 Grow an Existing Local Disk 34 Defragment an Existing Disk 34 Shrink an Existing Local Disk 35 Unlink Extents to Remove Disk 35 Shut Down 35 Disconnect from Server 35 Clean Up and Exit 35 Advanced Transport APIs 35 Initialize Virtual Disk API 35 Location of Log Files 37 List Available Transport Methods 37 Connect to VMware vSphere 37 Get Selected Transport Method 38 Prepare For Access and End Access 38 SAN Mode on Linux Uses Direct Mode 39 Clean Up After Disconnect 39 Updating Applications for Advanced Transport 39 Algorithm for vSphere Backup 39 4 VMware Inc Backup and Recovery Example 40 Best Practices for Backup 41 Licensing of Advanced Transports 41 Multithreading Considerations 41 Multiple Threads and VixDiskLib 41 Capabil
21. Inc 103 Virtual Disk Programming Guide 104 Disk Volume Information The VixVolumeInfo structure encapsulates the following information m Type of the volume VixVoLumeType one of the following Basic partition GPT GUID Partition Table Dynamic volume including Logical Disk Manager LDM LVM Logical Volume Manager disk storage m Whether the guest volume is mounted on the proxy m Path to the volume mount point on the proxy or NULL if the volume is not mounted m On Windows numGuestMountPoints is the number of times a basic volume is mapped to a drive letter or 0 if the volume is not mounted IDE and boot disk come first Unimplemented on Linux Mount points for the volume in the guest Function Calls To obtain these functions load the vixMntapi library separately from the vixDiskLib library On Windows compile with the vixMntapi lib library so your program can load the vixMntapi d11 runtime These calls can be used to mount and read Windows virtual disks on Windows hosts with at least one NTFS volume or Linux virtual disks on Linux hosts Cross mounting is restricted though it is possible to mount a virtual disk with a mix of formats if the mounted partition was formatted with Windows IMPORTANT You should run only one vixMntapi program at a time on a virtual machine to avoid conflict between registry hives See Multithreading Considerations on page 41 for advice on worker threads The remaind
22. T3 you can no longer obtain a list of changes between T1 and T2 2 Obtain the change ID for each virtual disk in the snapshot changeId_T3 per VMDK 3 Back up the sectors returned by queryChangedDiskAreas snapshot_T3 changeId_T2 A differential backup could be done with queryChangedDiskAreas snapshot_T3 changeId_T1 4 Delete snapshot_T3 keeping a record of changeId_T3 along with backed up data VMware Inc Virtual Disk API Functions For a disaster recovery at time T4 1 5 Create a new virtual machine with no guest operating system installed using configuration parameters you previously saved from VirtualMachineConfigInfo You do not need to format the virtual disks because restored data includes formatting information Restore data from the backup at time T3 Keep track of which disk sectors you restore Restore data from the incremental backup at time T2 skipping any sectors already recovered With differential backup you can skip copying the T2 backup Restore data from the full backup at time T1 skipping any sectors already recovered The reason for working backwards is to get the newest data while avoiding unnecessary data copying Power on the recovered virtual machine When programs open remote disk with SAN transport mode they can write to the base disk but they cannot write to a snapshot redo log Opening and writing snapshots is supported only for hosted disk Best Practices for Backup See T
23. access individual files or groups of files on the virtual disks For example data protection applications might need to restore individual files on demand You can find the interfaces to accomplish this in the VixMntapi library associated with VixDiskLib The VixMntapi library allows disks or volumes of a virtual machine to be mounted and examined as needed VixMntapi provides access at the file system level whereas VixDiskLib provides access at the sector level To mount a virtual disk 1 Locate the path names of all the virtual disks associated with a snapshot 2 Call VixDiskLib_Open to open all of these virtual disks This gives you a number of VixDiskLib handles which you should store in an array 3 Call VixMntapi_OpenDiskSet to create a VixDiskSetHand1Le passing in the array of VixDiskLib handles that you created in step 2 4 Pass VixDiskSetHand1e as a parameter to VixMntapi_GetVolumeHand les to obtain an array of VixVolumeHandle pointers to all volumes in the disk set 5 Call VixMntapi_GetOsInfo to determine what kind of operating system is involved and decide where important pieces of information are to be found 6 For important volumes call VixMntapi_MountVoLume then VixMntapi_GetVoLumeInfo which reveals how the volume is set up Unimportant volumes include swap partitions 7 If youneed information about how the guest operating system sees the data on this volume you can look in the data structure VixVoLumeInfo
24. accessed directly from inside a VM For example if you are running an iSCSI initiator within the virtual machine to access an iSCSI LUN from inside the VM vSphere cannot track it If the guest actually wrote to each block of a virtual disk long format or secure erase or if the virtual disk is thick and eager zeroed or cloned thick disk then the query reports the entire disk as being in use To find change information you can use the managed object browser at http lt ESXhost gt mob to follow path content gt rootFolder gt datacenter gt datastore gt vm gt snapshot gt config gt hardware gt virtualDisk gt backing Changed block tracking information changeId appears in the BackingInfo The following C code sample assumes that in the past you obtained a complete copy of the virtual disk and at the time when the changeId associated with the snapshot was collected you stored it for use at a later time which is now A new snapshot has been created and the appropriate moRef is available String changeld Already initialized changeId snapshotMoRef theVM ManagedObjectReference snapshotMoRef ManagedObjectReference theVM int diskDeviceKey Identifies the virtual disk VirtualMachine DiskChangeInfo changes long startPosition 0 do changes theVM queryChangedDiskAreas snapshotMoRef diskDeviceKey startPosition changelId for Cint i 0 i lt changes changedArea length i long length changes
25. apply to VMFS 5 volumes which always have 1MB file block size Table 3 2 VMFS 3 Block Size for HotAdd Backup Proxy VMFS Block Size Maximum Target Disk Size 1MB 256GB 2MB 512GB 4MB 1024GB 8MB 2048GB NBD and NBDSSL Transport When no other transport is available networked storage applications can use LAN transport for data access either NBD network block device or NBDSSL encrypted NBD is a Linux style kernel module that treats storage on a remote host as a block device NBDSSL is similar but uses SSL to encrypt all data passed over the TCP connection The NBD transport method is built into the virtual disk library so it is always available and is the fall back when other transport methods are unavailable VMware libraries and backup applications often fall back to NBD when other transports are unavailable Figure 3 3 LAN NBD Transport Mode for Virtual Disk ESX host backup server virtual machine VMware Tools application Virtual Disk API local storage In this mode the ESX ESXi host reads data from storage and sends it across a network to the backup server With LAN transport large virtual disks can take a long time to transmit This transport mode adds traffic to the LAN unlike SAN and HotAdd transport but NBD transport offers the following advantages m The ESX ESXi host can use any storage device including local storage or remote mounted NAS m The backup proxy can be a virtual ma
26. apply to an object of type Vapp Methods To Retrieve vApp Configuration m GetChildrenVms Gets a list of all child virtual machines that constitute a given vApp Returns List lt VM gt m GetStartupSection d Get virtual machine startup information Returns StartupSectionType m GetNetworksByName Get mapping of all the network sections using their name Returns Dictionary lt string NetworkSection_TypeNetwork gt m GetNetworkConfigSection Get network configuration details for a vApp The information typically contains IP scope gateway netmask DNS settings IP range Parent network Fence Mode settings and so on Returns NetworkConfigSectionType m GetLeaseSettingSection Get lease settings information It includes deployment and storage lease settings for the vApp Returns LeaseSettingsSectionType m GetOwnerQ Get owner information for the vApp Returns ReferenceType m GetMetadata Every resource in vCloud API can be associated with user defined metadata This method returns user defined metadata associated with a vApp Returns MetadataType VMware Inc 97 Virtual Disk Programming Guide 98 Example 8 10 shows the REST API calls used to get vApp configuration data Example 8 10 REST API Calls To Get vApp Configuration GET https vCloud api vapp id GET https vCloud api vapp id startupSection GET https vCloud api vapp id networkConnectionSection GET https vCloud api vapp id networkConfigSection
27. base disk of a powered on VM vix disklib sample info host vc5 user Administrator password secret mode san libdir usr lib vmware vix disklib 1lib64 vm vmPath Datacenter vm RHEL5 ssmoref snapshot 72 datastorel1 RHEL5 RHEL5S vmdk On Windows the VDDK package installs diskLibPlugin d11 in the bin folder not the lib folder so change lt pluginDir gt accordingly Walk Through of Sample Program The sample program is the same for Windows as for Linux with 1 fdef blocks for Win32 Include Files Windows dynamic link library DLL declarations are in process h while Linux shared object so declarations are in dlfcn h Windows offers the tchar h extension for Unicode generic text mappings not readily available in Linux Definitions and Structures The sample program uses twelve bitwise shift operations 1 lt lt 11 to track its available commands and the multithread option The Virtual Disk API has about 30 library functions some for initialization and cleanup The following library functions are not demonstrated in the sample program m VixDiskLib_Rename m VixDiskLib_Defragment m VixDiskLib_GrowQ m VixDiskLib_ShrinkO m VixDiskLib_UnlinkQO m VixDiskLib_AttachQ The sample program transmits state in the appGlobals structure VMware Inc 45 Virtual Disk Programming Guide 46 Dynamic Loading The 1 fdef DYNAMIC_LOADING block is long starting on line 97 and ending at line 339 This bloc
28. changedArea i Length long offset changes changedArea i startOffset Go get and save disk data here startPosition changes startOffset changes length while startPosition lt diskCapacity In the above code QueryChangedDiskAreas is called repeatedly as position moves through the virtual disk This is because the number of entries in the ChangedDiskArea array could occupy a large amount of memory for describing changes to a large virtual disk Some disk areas may have no changes for a given changeld The changed changed block ID contains a sequence number in the form lt UUID gt lt nnn gt If lt UUID gt changes it indicates that tracking information has become invalid necessitating a full backup Otherwise incremental backups can continue in the usual pattern VMware Inc Designing vSphere Backup Solutions Troubleshooting If you reconfigure a virtual machine to set changeTrackingEnab1ed but the property remains false check that you have queried the virtual machine status with VirtualMachine gt config after reconfiguration with VirtualMachine gt reconfigure and not before Also make sure that virtual machine compatibility is hardware version 7 or higher and that it has undergone a stun unstun cycle since reconfiguration Limitations on Changed Block Tracking Changed block tracking does not work if the virtual hardware version is 6 or earlier in physical compatibility RDM mode or when th
29. configuration and status information of managed objects using a piecemeal approach This has the severe disadvantage of creating a lot of chatter over the server connection so it is very slow A mechanism has been created to provide status information efficiently the PropertyCollector discussed in PropertyCollector Data on page 59 More About Managed Objects The documentation for the vSphere API and object model introduces a large number of managed objects There are five basic types of managed objects that describe the organization of a server Other managed objects can be considered as details expanding on these five basic types m Folder m Datacenter ComputeResource m ResourcePool m VirtualMachine It is a characteristic of all managed objects that they have a moRef to the managed object that serves as the parent to the managed object This parent moRef allows you to reconstruct the object hierarchy exposed by the vSphere SDK In general the hierarchy is a tree like structure along the lines of Root Folder gt Datacenter gt ComputeResource gt ResourcePool gt VirtualMachine There are variations on this theme depending on whether you connect to vCenter or directly to an ESXi host but the overall organization is like the structure above Each managed object also has a Name property The virtual machine that you want to back up and the snapshot you take of it the extensible managed object VirtualMachineSnapshot ar
30. connections to an ESX ESXi host credentials including user name and password must be correctly supplied in the user and password command line arguments Both the host name of the ESX ESXi host and its vm inventory path vmxSpec must be supplied When set these values populate the cnxParams structure Initialize all parameters especially vmxSpec or else the connection might behave unexpectedly A call to VixDiskLib_Init initializes the library In a production application you can supply appropriate log warn and panic functions as parameters in place of NULL A call to VixDiskLib_Connect creates a connection to disk If host cnxParams serverName is null as itis without the host argument a connection is made to hosted disk on the local host Otherwise a connection is made to managed disk on the remote host With ssmoref argument advanced transport is used Next an appropriate function is called for the requested operation followed by error information if applicable Finally the main O function closes the library connection to disk and exits Dolnfo This procedure calls VixDiskLib_GetInfo for information about the virtual disk displays results and calls VixDiskLib_FreeInfo to reclaim memory The parameter disk Handle comes from the VixDisk wrapper class discussed in Wrapper Classes on page 46 In this example the sample program connects to an ESX ESXi host named esx5 and displays virtual disk information for
31. for hosted disk and the only setting in the Chapter 5 sample program VIXDISKLIB_DISK_MONOLITHIC_FLAT Preallocated virtual disk contained in a single virtual disk file This takes time to create and occupies a lot of space but might perform better than sparse VIXDISKLIB_DISK_SPLIT_SPARSE Growable virtual disk split into 2GB extents s sequence These files can to 2GB then continue growing in a new extent This type works on older file systems VIXDISKLIB_DISK_SPLIT_FLAT Preallocated virtual disk split into 2GB extents f sequence These files start at 2GB so they take a while to create but available space can grow in 2GB increments VIXDISKLIB_DISK_VMFS_FLAT Preallocated virtual disk compatible with ESX 3 and later Also known as thick disk This managed disk type is discussed in Managed Disk and Hosted Disk on page 13 VIXDISKLIB_DISK_VMFS_SPARSE Employs a copy on write COW mechanism to save storage space VIXDISKLIB_DISK_VMFS_THIN Growable virtual disk that consumes only as much space as needed compatible with ESX 3 or later supported by VDDK 1 1 or later and highly recommended VIXDISKLIB_DISK_STREAM_OPTIMIZED Monolithic sparse format compressed for streaming Stream optimized format does not support random reads or writes 19 Virtual Disk Programming Guide 20 Persistence Disk Modes In persistent disk mode changes are immediately and permanently written to the virtual disk so that the
32. function calls VixDiskLib_GetInfoQ to determine the number of sectors allocated in the virtual disk The number of sectors is available in the VixDiskLibDiskInfo structure but normally not in the metadata With SPARSE type layout data can occur in any sector so this function reads all sectors whether filled or not VixDiskLib_Read continues without error when it encounters an empty sector full of zeroes The following difference list shows the remaining code changes necessary for adding the virus option to the vixDiskLibSample cpp sample program 43a44 gt define COMMAND_VIRUS_SCAN 1 lt lt 10 72a74 gt static void DoVirusScan void 425a429 gt printf virus scan source vmdk for virus signature n 519a524 525 gt else if appGlobals command amp COMMAND_VIRUS_SCAN gt DoVirusScan 564a571 572 gt else if strcmp argv i virus gt appGlobals command COMMAND_VIRUS_SCAN Creating Virtual Disks 50 This section discusses the types of local VMDK files and how to create virtual disk for a remote ESX ESXi host Creating Local Disk The sample program presented in Chapter 5 creates virtual disk of type MONOLITHIC_SPARSE in other words one big file not pre allocated This is the default because modern file systems in particular NTFS support files larger than 2GB and can hold more than 2GB of total data This is not true of legacy file systems such as FAT16 on MS DOS and early Windows
33. level for NFC operations The default value is 1 indicating error messages only The meaning of values is listed below Each level includes all of the messages generated by lower numbered levels above This is the final NFC setting 0 Quiet minimal logging 1 Error 2 Warning 3 Info 4 Debug Example 4 1 Sample InitEx configuration file tmpDirectory usr Local vendorapp var vmware temp log level to 6 for quiet ranging to verbose vixDiskLib transport LogLevel 2 disable caching to disk vixDiskLib diskLib EnablLeCache 0 whether to check SSL thumbprint on Linux vixDiskLib LinuxSSL verifyCertificates 0 network file copy options vixDiskLib nfc AcceptTimeoutMs 180000 vixDiskLib nfc RequestTimeoutMs 180000 vixDiskLib nfc ReadTimeoutsMs 60000 vixDiskLib nfc WriteTimeoutsMs 600000 vixDiskLib nfcFssrvr TimeoutMs 0 vixDiskLib nfcFssrvrwWrite TimeoutMs 0 nfc LogLevel 0 Quiet 1 Error 2 Warning 3 Info 4 Debug vixDiskLib nfc LogLevel 2 VMware Inc Virtual Disk API Functions Timeout values are stored in a 32 bit field so the maximum timeout you may specify is 2G 2 147 483 648 Timeouts are specified in milliseconds and apply to each disk handle NFC settings apply to NBD NBDSSL but not to SAN or HotAdd Location of Log Files On Linux log messages appear under var 1og by default On Windows they appear in a temporary folder whose location can change from time to time Early Windo
34. library reads the VMFS header and matching UUID But for RDM the host and proxy require the same LUN ID Restoring RDM disks is appropriate if the original virtual machine s VMX file and disk mapping is no longer available but the LUN containing the RDM is still available In this case the RDM image on the LUN might still be valid so it does not need to be restored If this is true do not make changes to the RDM configuration during your restore operations Instead complete the restore process in two phases m Restore the virtual machine configuration VMX and system disk This restores the virtual machine but does not restore the RDM m Add the RDM disk to the virtual machine After doing so you can complete normal restore operations on the RDM disk Alternatively it is possible to create a virtual machine that can host the RDM disk and access its contents After you create the virtual machine restore its virtual machine configuration VMX from backup and then restore any selected disks Restoring the Virtual BIOS or UEFI The nvram file stores the BIOS or UEFI customizations of a virtual machine Usually the only important items in this file are the boot drive setting and the boot order in the case of multiple virtual disks Newer releases of vSphere can change the boot order using extended attribute settings so boot order no longer must be stored in the nvram file However some users want to preserve a virtual machine s
35. maintenance mode for the vApp to prevent changes while restoring metadata Edit vApp settings such as network user privileges lease and quota as needed Make sure to include any user defined metadata from the backup store If you restored a virtual machine to a different location from the original you might need to adjust the vApp settings Deselect maintenance mode for the vApp You might want to restore a missing vApp because somebody deleted it or as part of disaster recovery To restore a missing vApp 1 2 7 Identify the child virtual machines of the vApp using the metadata stored with the backup Connect to vCenter Server as a user with sufficient permissions to access the virtual machines and restore the virtual machines in the vSphere environment This step restores the virtual disk files and virtual machine configuration Connect to vCloud Director and authenticate as an administrator which gives you backup and restore privileges Compose a new vApp or import the virtual machine s into vCloud Director to create a new vApp with these characteristics a It has the same name as the lost vApp b It belongs to the same Organization as the lost vApp c It obtains resources from the same provider VDC as the lost vApp Select maintenance mode for the vApp to prevent changes while restoring metadata Edit vApp settings such as network user privileges lease and quota as needed Make sure to include any user defined
36. must specify the options host user password and provide a diskPath on the ESXi host s datastore For example vix diskLib sample info host esx5 user root password secret datastorel lt VM gt lt VM gt vmdk To connect to vCenter Server you must also specify the options libdir and vm Programs need libdir so the DiskLibPlugin can connect with vCenter Server which must locate the VM For example vix diskLib sample info host vc5 user Administrator password secret libdir lt pluginDir gt vm vmPath lt path to VM gt lt partition gt lt VM gt lt VM gt vmdk The vmPath is formulated in vSphere Client by starting at vCenter and inserting vm before the VM name The diskPath is ascertained by clicking Edit Settings gt Hard Disk and copying the Disk File name vix disklib sample info host vc5 user Administrator password secret libdir usr lib vmware vix disklib 1lib64 vm vmPath Datacenter vm RHEL5 datastore1 RHEL5 RHELS vmdk To connect using an advanced transport for example to virtual machine disk on SAN storage you must also specify the options mode and ssmoref The transport mode and managed object reference of a snapshot are required for VixDiskLib_ConnectEx To find the ssmoref log in to the managed object browser for the vCenter Server and click content gt rootFolder gt Datacenter gt datastore gt vm gt snapshot A snapshot must exist because it is a bad idea to open the
37. need a reference to its parent Organization 92 VMware Inc Backing Up vApps in vCloud Director You use the Organization reference to get the Organization object which you use to get a list of references to the VDCs that belong to the Organization You use a VDC reference to get a VDC object which you then use to get a list of references to the vApps that belong to the Organization You convert the desired vApp reference to a vApp object which you use to list the virtual machines that belong to the vApp Example 8 1 shows how to get a reference to the user view of an Organization Example 8 2 shows how to get a reference to the admin view of an Organization and a VDC Example 8 2 Get Admin Org and Admin VDC public static vCloudClient client null Login Get admin view of Org VcLloudAdmin admin client GetVcLoudAdmin string orgName Org1 ReferenceType orgRef admin GetAdminOrgRefByName orgName AdminOrganization adminOrg Organization AdminGetOrgByReference client orgRef Get admin vDC string vdcName VDC1 ReferenceType vdcRef adminOrg GetAdminVdcRefByName vdcName AdminVdc adminVdc AdminVdc GetAdminVdcByReference client vdcRef Admin Views The admin view of resources such as Organization VDC and vApp provides extra information that is useful to users with administrative privileges For example in the case of a vApp admin view provides information about vCenter and the vir
38. no traffic on the communications thread unless something must be reported The PropertyCollector is powerful but requires great attention to detail Backup related features of the PropertyCollector are covered in Low Level Backup Procedures on page 64 of this document The next section provides some background about PropertyCol lector PropertyCollector Data This document assumes that you want to keep up with changes in the configuration of the vCenter Server and therefore plan to use the update tracking capability of the PropertyCollector The PropertyCol lector requires two fairly complex arguments the PropertySpec and the ObjectSpec The ObjectSpec contains instructions to the PropertyCollector describing where to look for the desired data Because configuration information in vSphere is organized like a directory tree the ObjectSpec must describe how to traverse the tree to obtain the desired information The net result is a complex nested and recursive list of instructions Fortunately once you have determined the location of all the desired information the ObjectSpec needed to determine the layout of a vSphere object hierarchy can be a static unvarying object See the code example in section Understanding an ObjectSpec on page 64 The PropertySpec isa list of desired property information Formulating a list that includes all of the desired information can take some effort to compile but once determined this can be a static
39. on page 57 Platform Product Compatibility To support a new release of vSphere in most cases you should update and recompile your software with a corresponding new release of VDDK This is because VDDK is continually updated to support new features in vSphere As of 5 0 the version number of VDDK matches the version number of vSphere Since its inception in 2008 VDDK has been backward compatible with VMware platform products such as Workstation ESX ESXi and vCenter Server formerly VirtualCenter VMware Fusion was never supported Redistributing VDDK Components After you use the VDDK to develop software applications that run on VMware platform products you might need to repackage library components that are compiled into your software To qualify for VDDK redistribution you must be in the VMware TAP program at Select level or above and sign a redistribution agreement Contact your VMware alliance manager to request the VDDK redistribution agreement VMware would like to know how you use the VDDK in what products you plan to redistribute it your company name and your contact information VMware Inc Installing the Development Kit To develop virtual disk applications install the VDDK as described in this chapter For backup applications VADP development also requires the vSphere Web Services SDK m Prerequisites on page 15 m Installing the VDDK Package on page 16 Prerequisites This section covers what yo
40. or VMware vCenter contained within a VMFS volume monolithic The virtual disk is a single VMDK file rather than a collection of 2GB extents Contrast with split N NBD Network block device a VMware method for over the network access P proxy A physical or virtual machine running an operating system with third party backup software The proxy is used to perform file level and image level virtual machine backups Q quiescing A method of bringing the on disk data of a physical or virtual computer into a state suitable for backups Quiescing may include flushing disk buffers from the operating system s in memory cache or other tasks R RDM Raw Device Mapping Enables a virtual machine to directly access a LUN on the physical storage subsystem SAN connected by Fibre Channel iSCSI or SAS At the same time the virtual machine has access to the disk that is using a mapping file in the VMFS name space Performance is similar to VMDK VMware Inc 113 Virtual Disk Programming Guide S sparse Space in a VMDK is allocated only when needed to store data Contrast with flat split The virtual disk is a collection of VMDK files containing 2GB extents Contrast with monolithic V VMDK Virtual Machine DisK The virtual counterpart to a guest operating system s physical disk A file or group of files that can reside on the host machine or on a remote file system VMFS Virtual Machine File System A file system optimized for storing
41. overhead not VDDK advanced transports However once thin disk has been created performance is similar to thick disk as discussed in the Performance Study of VMware vStorage Thin Provisioning When applications perform random I O or write to previously unallocated areas of thin provisioned disk subsequent backups can be larger than expected even with CBT enabled In some cases disk defragmentation might help reduce the size of backups Virtual Machine Configuration Do not make verbatim copies of configuration files which can change For example entries in the vmx file point to the snapshot not the base disk The vmx file contains virtual machine specific information about current disks and attempting to restore this information could fail Instead use PropertyCol Lector and keep a record of the ConfigInfo structure About Changed Block Tracking QueryChangedDiskAreas returns information about areas of a virtual disk that are in use allocated The current implementation depends on VMFS properties similar to properties that SAN transport mode uses to locate data on a SCSI LUN Both rely on unallocated areas file holes in virtual disk and the LazyZero designation for VMFS blocks Thus changed block tracking yields meaningful results only on VMFS On other storage types it either fails or returns a single extent covering the entire disk You should enable changed block tracking in the order recommended by Enabling Changed
42. snapshot will cause restore problems for subsequent backups VMware Inc 73 Virtual Disk Programming Guide 74 Creating a Virtual Machine This section shows how to create a VirtualMachine object which is complicated but necessary so you can restore data into it Before creating this object you must create a VirtualMachineConfigSpec describing the virtual machine and all of its supporting virtual devices Almost all the required information is available from the virtual machine property config hardware device which is a table containing the device configuration information The relationships between devices are described by the value key which is a unique identifier for the device In turn each device has a controllerKey which is the key identifier of the controller where the device is connected Use negative integers as temporary key values in the VirtualMachineConfigSpec to guarantee that temporary key numbers do not conflict with real key numbers when they are assigned by the server When associating virtual devices with default devices the controllerKey property should be reset with the key property of the controller Below are the settings for a sample Virtua lMachineConfigSpec used to create a virtual machine beginning of VirtualMachineConfigSpec ends several pages later dynamicType lt unset gt changeVersion lt unset gt This is the display name of the VM name My New VM version vmx 04 uuid lt
43. supported on vSphere 5 5 and later POSIX based file systems including NFS version 3 no longer have a 2GB file size limit Although various checks are done to avoid creating impossibly large files it becomes the customer s responsibility to cope with 2GB limits on NFS version 2 or Linux kernel 2 4 EFS Open a Local or Remote Disk After the library connects to a workstation or server VixDiskLib_Open opens a virtual disk With SAN or HotAdd transport opening a remote disk for writing requires a pre existing snapshot vixError VixDiskLib_Open appGlobals connection appGlobals diskPath appGlobals openFlags amp srcHand1le The following flags modify the open instruction m VIXDISKLIB_FLAG_OPEN_UNBUFFERED Disable host disk caching m VIXDISKLIB_FLAG_OPEN_SINGLE_LINK Open the current link not the entire chain hosted disk only m VIXDISKLIB_FLAG_OPEN_READ_ONLY Open the virtual disk read only Read Sectors From a Disk VixDiskLib_Read reads a range of sectors from an open virtual disk You specify the beginning sector and the number of sectors Sector size could vary but is defined in lt vixDiskLib h gt as 512 bytes because VMDK files have that sector size vixError VixDiskLib_Read srcHandle i j buf Write Sectors To a Disk VixDiskLib_Write writes one or more sectors to an open virtual disk This function expects the fourth parameter buf to be VIXDISKLIB_SECTOR_SIZE bytes long vixError VixDi
44. supports Unicode UTF 8 path names although for portability to various locales ASCII only path names are recommended Windows 2000 systems and later use UTF 16 for localized path names For example in locale FR Frangais the VDDK sample code might mount disk at C Windows Temp vmware Systeme where is encoded as UTF 16 so the VixMntapi library cannot recognize it In this case a workaround is to set the tmpDirectory configuration key with an ASCII only path before program start up see Initialize the Library on page 29 For programs opening arbitrary path names Unicode offers a GNU library with C functions iconv_open to initialize codeset conversion and iconv to convert UTF 8 to UTF 16 or UTF 16 to UTF 8 Virtual Disk Internal Format The Virtual Disk Format 5 0 technical note provides possibly useful information about the VMDK format and is available at this URL http www vmware com support developer vddk vmdk_50_technote pdf Grain Directories and Grain Tables SPARSE type virtual disks use a hierarchical representation to organize sectors See Virtual Disk Format 5 0 referenced in Virtual Disk Internal Format on page 21 In this context grain means granular unit of data larger than a sector The hierarchy includes m Grain directory and redundant grain directory whose entries point to grain tables m Grain tables and redundant grain tables whose entries point to grains m Each grain is a block of sec
45. the type of the backing property to one of the following or a VirtualMachineSnapshot managed object VirtualDiskFlatVer1BackingInfo VirtualDiskFlatVer2BackingInfo VirtualDiskRawDiskMappingVer1BackingInfo VirtualDiskSparseVer1BackingInfo VirtualDiskSparseVer2BackingInfo It is important to know which backing type is in use in order to be able to re create the Virtual Disk It is also important to know that you cannot snapshot a disk of type VirtualDiskRawDiskMappingVer1BackingInfo and therefore you cannot back up this type of Virtual Disk The properties of interest are the backing fi leName and the VirtualDisk capacityInkB Additionally when change tracking is in place you should also save the changeID VMware Inc Designing vSphere Backup Solutions Creating a Snapshot Before performing a backup operation you must create a snapshot of the target virtual machine Both full and incremental backup rely on the snapshot in vSphere With SAN transport on VMFS volumes the virtual machine should not have any pre existing snapshots so that reporting of in use disk sectors will work For details see About Changed Block Tracking on page 83 As a best practice you should search for and delete any pre existing snapshots with the same name that you selected for the temporary snapshot These snapshots are possibly remnants from failed backup attempts Within a specific snapshot the names of virtual disk files with extension vmdk
46. to a volume m info out Volume information to be filled in VixMntapi_FreeVolumelInfo Frees memory allocated in VixMntapi_GetVolumeInfo void VixMntapi_FreeVoLumeInfo VixVolumeInfo info Parameter m info in Volume info to be freed VMware Inc 107 Virtual Disk Programming Guide Programming with VixMntapi 108 At the top of your program include vixMntapi h along with any other header files you need Structures and type definitions are declared in the include file so you do not need to create them or allocate memory for them Call VixMntapi_Init to initialize the library in your application This function takes major and minor version number to account for future extensions You can provide your own logging warning or panic functions to substitute for the default VixMntapi handlers and custom library and temporary directories Call VixMntapi_OpenDiskSet to open a set of virtual disks for mounting Pass a set of disk handles obtained from the VixDiskLib_Open call The VixMntapi_OpenDiskSet function also expects number of disks to open an optional open mode and a parameter to pass back the resulting disk set handle File System Support Windows file systems FAT FAT32 and NTFS are supported The vixMntapi library depends on the operating system for file system attributes such as compression encryption hidden ACL and alternate streams If a vixMntapi linked application runs on a virtual machine th
47. transports allow programs to transfer data in the most efficient manner SAN transport is available only when the physical machine host has SAN access HotAdd works for the appliance model where backup is done from inside virtual machines HotAdd requires the virtual machine datastore to be accessible from the backup appliance NBDSSL is a secure fallback when over the network backup is your only choice SAN transport is supported only on physical machines and HotAdd transport is supported only on virtual machines SAN requires a physical proxy to share a LUN with the ESXi host where a datastore resides enabling direct access to raw data and bypassing the host altogether for I O operations HotAdd involves attaching a virtual disk to the backup proxy just like attaching the disk to a virtual machine Best Practices for SAN Transport For array based storage SAN transport is often the best performing choice for backups when running on a physical proxy It is disabled inside virtual machines so use SCSI HotAdd instead on a virtual proxy VMware Inc 81 Virtual Disk Programming Guide 82 SAN transport is not always the best choice for restores It offers the best performance on thick disks but the worst performance on thin disks because of round trips through the disk manager APIs ALlocateBlock and ClearLazyZero For thin disk restore NBDSSL is usually faster and NBD is even faster Changed Block Tracking CBT must be disabled for SAN r
48. unset gt instanceUuid lt unset gt npivWorldWideNameType lt unset gt npivDesiredNodeWwns lt unset gt npivDesiredPortWwns lt unset gt npivTemporaryDisabled lt unset gt npivOnNonRdmDisks lt unset gt npivWorldwideNameOp lt unset gt locationId lt unset gt This is advisory the disk determines the 0 S guestId winNetStandardGuest alternateGuestName Microsoft Windows Server 2008 Enterprise Edition annotation lt unset gt files vim vm FileInfo dynamicType lt unset gt vmPathName pLat004 Local snapshotDirectory plat004 local suspendDirectory lt unset gt logDirectory lt unset gt Fs tools vim vm ToolsConfigInfo dynamicType lt unset gt toolsVersion lt unset gt afterPowerOn true afterResume true beforeGuestStandby true beforeGuestShutdown true beforeGuestReboot true toolsUpgradePolicy lt unset gt pendingCustomization lt unset gt syncTimeWithHost lt unset gt flags vim vm FlagInfo dynamicType lt unset gt disableAcceleration lt unset gt enableLogging lt unset gt useToe lt unset gt runWithDebugInfo lt unset gt monitorType lt unset gt htSharing lt unset gt snapshotDisabled lt unset gt snapshotLocked lt unset gt diskUuidEnabled lt unset gt virtualMmuUsage lt unset gt snapshotPowerOffBehavior powerOff recordRepLayEnabled lt unset gt VMwar
49. 1lib 1ib64 into usr 1ib Open Source Components 112 VDDK contains the following open source components with license types indicated Boost BSD style license Curl MIT X derivative license Expat BSD style license FreeBSD BSD license ICU International Components for Unicode BSD style license LibXML2 MIT style license OpenLDAP OpenLDAP v 2 8 license OpenSSL OpenSSL license Zlib BSD license These open source components have the GNU library general public license GetText LGPL2 0 Glib LGPL 2 0 LibFuse LGPL2 0 LibIconv LGPL2 0 VMware Inc Glossary Cc changed block tracking CBT A VMware feature that keeps track of which blocks in a virtual disk changed since the time of inception or when CBT was last enabled Developers of backup and recovery software can use the CBT feature to help reduce data size for differential or incremental backup D differential backup Saving system data changed since the last full backup so only two restore steps are necessary E extent In the context of VMDK a split portion of virtual disk usually 2GB F flat Space in a VMDK is fully allocated at creation time pre allocated Contrast with sparse H hosted disk A virtual disk stored on a hosted product such as VMware Workstation for its guest operating system l incremental backup Saving system data changed since the last backup of any type M managed disk A virtual disk managed by an ESX ESXi host
50. 3 temporary 60 snapshot management 53 snapshots and redo logs 20 22 32 53 sparse VMDK 19 20 32 34 44 47 48 50 114 split VMDK 19 20 50 114 SPLIT_FLAT 19 20 SPLIT_SPARSE 19 20 SSL certificate 26 STREAM_OPTIMIZED 19 supported platforms for development 15 supported VMware products 15 T thin provisioned disk 21 thumbprint SSL 26 U UEFI unified extensible firmware interface 54 Unicode UTF 8 support 21 unique ID and moRef 59 V vCloud and vCloud Director 12 verify SSL certificate 26 versions of VMDK files 51 VHD from Microsoft 22 Vim find_entity_views in Perl toolkit 56 Vim get_inventory_path in Perl toolkit 56 virtual disk manager vmware vdiskmanager 12 VirtualMachineConfigInfo 39 VirtualMachineConfigSpec 74 Visual Studio 15 VixDiscoveryProc 55 VIXDISKLIB_ADAPTER_IDE 23 50 VIXDISKLIB_ADAPTER_SCSI_BUSLOGIC 23 50 VIXDISKLIB_ADAPTER_SCSI_LSILOGIC 23 VixDiskLib_Attach 28 33 47 53 VixDiskLib_Clone 28 32 42 48 51 VixDiskLib_Close 28 30 46 VixDiskLib_Connect 28 29 42 46 48 52 VixDiskLib_Create 28 30 42 47 50 51 53 VixDiskLib_CreateChild 28 33 47 VIXDISKLIB_CRED_UID 52 VixDiskLib_Defragment 28 34 42 VixDiskLib_ Disconnect 28 35 VIXDISKLIB_DISK_SPLIT_SPARSE 50 VixDiskLib_EndAccess 28 VixDiskLib_Exit 28 35 VixDiskLio_FreeErrorText 28 31 VixDiskLib_Freelnfo 28 31 46 VixDiskLib_GetErrorText 28 31 VixDiskLib_GetInfo 28 30 46 49 50 VixDiskLib_GetMetadataKeys 28 31 47 Vi
51. 55 Scan VMDK for Virus Signatures One of the Use Cases for the Virtual Disk Library on page 12 is to scan a VMDK for virus signatures Using our sample program framework the function in Example 6 1 implements the virus command line option using hypothetical library routine SecureVirusScan supplied by an antivirus software vendor The library routine scans a buffer against the vendor s latest pattern library returning TRUE if it identifies a virus Example 6 1 Function to Scan VMDK for Viruses extern int SecureVirusScan const uint8 amp buf size_t n DoVirusScan Scan the content of a virtual disk for virus signatures 7 static void DoVirusScan void VixDisk disk appGlobals connection appGlobals diskPath appGlobals openFlags VixDiskLibDiskInfo info uint8 buf VIXDISKLIB_SECTOR_SIZE VixDiskLibSectorType sector VixError vixError VixDiskLib_GetInfo disk HandleQ amp info CHECK_AND_THROW vixError cout lt lt capacity lt lt info capacity lt lt sectors lt lt endl read all sectors even if not yet populated for sector 0 sector lt info capacity sector vixError VixDiskLib_Read disk Handle sector 1 buf CHECK_AND_THROWCvixError if SecureVirusScan buf sizeof buf printfC Virus detected in sector d n sector cout lt lt info capacity lt lt sectors scanned lt lt endl VMware Inc 49 Virtual Disk Programming Guide This
52. ADAPTER_SCSI_BUSLOGIC Virtual SCSI disk with Buslogic adapter This is the default on some platforms and is usually recommended over IDE due to higher performance m VIXDISKLIB_ADAPTER_SCSI_LSILOGIC Virtual SCSI disk with LSI Logic adapter Windows Server 2003 and most Linux virtual machines use this type by default Performance is about the same as Buslogic Virtual Disk Transport Methods VMware supports file based or image level backups of virtual machines hosted on an ESX ESXi host with SAN or NAS storage Virtual machines read data directly from a shared VMFS LUN so backups are efficient and do not put significant load on production ESX ESXi hosts or the virtual network VMware offers interfaces for integration of storage aware applications including backup with efficient access to storage clusters Developers can use VDDK advanced transports which provide efficient I O methods to maximize backup performance VMware supports five access methods local file NBD network block device over LAN NBD with encryption NBDSSL SAN and SCSI HotAdd Local File Access The virtual disk library reads virtual disk data from vmfs volumes on ESX ESXi hosts or from the local file system on hosted products This file access method is built into VixDiskLib so it is always available on local storage However it is not a network transport method and is seldom used for vSphere backup SAN Transport SAN mode requires applications to run on a
53. AM nightly although multiple snapshots have a performance impact When you create a redo log while the virtual machine is running the VMware host re arranges file pointers so the primary VMDK lt vmname gt vmdk for example keeps track of redo logs in the disk chain Use the disk chain to re create data for any given day To re create data for any given day 1 Locate the lt vmname gt lt NNN gt vmdk redo log for the day in question lt NNN gt is a sequence number You can identify this redo log or snapshot by its timestamp 2 Initialize the virtual disk library and open the redo log to obtain its parent handle 3 Create a child disk with the VixDiskLib_Create function and attach it to the parent vixError VixDiskLib_Attach parent HandleQ child Handle 4 Read and write the virtual disk of the attached child This is just an example On managed disk multiple snapshots are not recommended for performance reasons Backup software on vSphere usually takes a snapshot saves data to backup media then deletes the snapshot Virtual Disk in Snapshots The Virtual Disk API provides the following features to deal with the disk component of snapshots m Attaching an arbitrary child in a disk chain m Opening read only virtual disks m Ability to open snapshot disk on ESX ESXi hosts through VMware vCenter Windows 2000 Read Only File System Another use of parent child disk chaining is to create read only access for Windows 2000 which h
54. As in the section Low Level Restore Procedures on page 73 VixDiskLib functions provide interfaces for writing the data to virtual disk either locally or remotely Raw Device Mapping RDM Disks To create an RDM disk using CreateVM_Task use a LUN that is not occupied and thus is still available Developers sometimes use the same LUN uuid that is available in the configInfo object which can cause errors because the LUN uuid is datastore specific Call QueryConfigTarget to fetch the ConfigTarget ScsiDisk Disk CanonicalName property set in VirtualDiskRawDiskMappingVer1BackInfo deviceName Also call QueryConfigTarget to fetch ConfigTarget ScsiDisk Disk uuid set in VirtualDiskRawDiskMappingVer1BackInfo LunUuid When creating the virtual machine avoid host specific properties of configInfo which should be set according to host configuration where the virtual machine is restored Restore of Incremental Backup Data At some point you might need to restore a virtual disk from the backup data that you gathered as described in Changed Block Tracking on Virtual Disks on page 70 The essential procedure is as follows 1 Power off the virtual machine if powered on 2 Using VirtualMachineConfigInfo that corresponds to the last known good state of the guest operating system re create the virtual machine as described in Using the VirtualMachineConfigInfo on page 79 80 VMware Inc Designing vSphere Backup Solutions 3 Completel
55. Block Tracking on page 71 The first time you call QueryChangedDiskAreas it should return allocated areas of virtual disk Subsequent calls return changed areas instead of allocated areas If you call QueryChangedDiskAreas after a snapshot but before you enable changed block tracking it also returns unallocated areas of virtual disk With thin provisioned virtual disk this could be a large amount of zero data The guest operating system has no visibility of changed block tracking Once a virtual machine has written to a block on virtual disk the block is considered in use The information required for the query is computed when changed block tracking is enabled and the ctk file is pre filled with allocated blocks The mechanism cannot report changes made to virtual disk before changed block tracking was enabled VMware Inc 83 Virtual Disk Programming Guide HotAdd and SCSI Controller IDs When using HotAdd backup always add SCSI controllers to virtual machines in numeric order Most systems lack an interface to report which SCSI controller is assigned to which bus ID HotAdd assumes that the unique ID for a SCSI controller corresponds to its bus ID This assumption could be false For instance if the first SCSI controller on a VM is assigned to bus ID 0 but you add a SCSI controller and assign it to bus ID 3 HotAdd transport may fail because it expects unique ID 1 To avoid problems when adding SCSI controllers to a VM the
56. Cloud SDK for NET also supports the query service of the vCloud API for finding vApps Consult the sample programs in the SDK for more information about how to use the query service in the SDK Protecting Specified vApps Backup systems typically identify vApps to be backed up in a given Organization based on their identity using vApp attributes such as name and ID or user defined metadata A set of vApps to be backed up can also be created based on their Organization for example all vApps in the Human Resources Organization the VDC where they are deployed and so forth In all these cases you must traverse the given Organization and its contents to locate and make a list of vApps Recovering an Older Version of a vApp If a vApp has become corrupted or if users need to revert to an older state of the vApp the administrator can restore a version of the vApp from backup storage even when the vApp still exists in vCloud Director The backup restore application in these cases can access vCloud Director to get vApp identity information and metadata before restoring the backup copy The backup restore application has a choice between overwriting the current vApp instance or deleting it and creating a new vApp The choice to delete the vApp can be convenient when the vApp configuration has changed since the last backup especially when a virtual machine has been added to or deleted from the vApp Recovering a Deleted vApp When recovering a del
57. Cloud api admin org id GET https vCloud api admin vdc id GET https vCloud api admin extension GET https vCloud api admin extension providervdc id You can use a provider VDC reference to enumerate its associated datastores as shown in Example 8 7 This example assumes you have already logged in to vCloud Director Example 8 7 List Datastores lt Summary gt Returns list of Provider vDCs lt summary gt lt returns gt ReferenceType lt returns gt public static List lt ReferenceType gt GetProviderVdc List lt ReferenceType gt vdcRefList new List lt ReferenceType gt foreach ReferenceType vdcRef1 in client GetVcloudAdminExtension GetVMWProviderVdcRefsByName Values vdcRefList Add vdcRef1 return vdcRefList lt summary gt Returns the list of DataStores lt summary gt lt returns gt ReferenceType lt returns gt public static List lt ReferenceType gt GetDataStore extension client GetVcloudAdminExtension List lt ReferenceType gt vmDatastorelist new List lt ReferenceType gt foreach ReferenceType datastoreRef in extension GetVMwDatastoreRefs vmDatastorelist Add datastoreRef return vmDatastorelist Get the datastores for the list of Provider vDCs foreach ReferenceType providerVdcRef in GetProviderVdc string providerVdcId GetId providerVdcRef href Console WriteLine Provider vDC Id providerVdcId
58. DiskLib linuxSSL verifyCertificates Whether to check for SSL thumbprint when connecting to a Linux virtual machine Possible values are 0 for Off and 1 for On Default is 0 The following NFC related options override the default numbers provided to the various NFC functions The NFC timeouts shown in Example 4 1 correspond to default values on ESXi 5 x hosts vixDiskLib nfc AcceptTimeoutMs Overrides default value 3 minutes for NFC accept operations vixDiskLib nfc RequestTimeoutMs Overrides default value 3 minutes for NFC request operations vixDiskLib nfc ReadTimeoutMs Overrides default value one minute for NFC read operations vixDiskLib nfc WriteTimeoutMs Overrides default value ten minutes for NFC write operations vixDiskLib nfcFssrvr TimeoutMs Overrides the default value default is 0 indefinite waiting for NFC file system operations If you specify a value then a timeout occurs if the file system is idle for the indicated period of time The hazard of using the default value is that in the rare case of a catastrophic communications failure the file system will remain locked vixDiskLib nfcFssrvrWrite TimeoutMs Overrides the default value default is no timeout for NFC file system write operations The timeout is specifed in milliseconds If you specify a value it will time out when a write operation fails to complete in the specified time interval vixDiskLib nfc LogLevel Overrides the default logging
59. FS_THIN If you select only the Allocate all disk space now check box space is pre allocated so the virtual disk cannot grow The first VMDK file is small and points to a much larger one whose filename says flat without a sequence number Similarly on VMFS partitions this is the virtual disk file that points to virtual disk data files either thick or thin provisioned lt vnname gt flat vmdk SPLIT_SPARSE If you select only the Split disk into 2GB files check box virtual disk can grow when more space is needed The first VMDK file is small and points to a sequence of other VMDK files all of which have an s before a sequence number meaning sparse The number of VMDK files depends on the disk size requested As data grows more VMDK files are added in sequence lt vmname gt s lt gt vmdk SPLIT_FLAT If you select the Allocate all disk space now and Split disk into 2GB files check boxes space is pre allocated so the virtual disk cannot grow The first VMDK file is small and points to a sequence of other files all of which have an f before the sequence number meaning flat The number of files depends on the requested size lt vnname gt f lt gt vmdk MONOLITHIC_SPARSE or SPLIT_SPARSE snapshot A redo log or child disk or delta link is created when a snapshot is taken of a virtual machine or with the virtual disk library Snapshot file numbers are in sequence without an s or f prefix The nu
60. Guest OS Guest OS Guest OS The VDDK supports both managed disk and hosted disk although some functions are not supported for managed disk and other facilities are not supported for hosted disk Exceptions are noted in documentation VMware Inc 13 Virtual Disk Programming Guide 14 Advanced Transports With managed disk VDDK applications can make use of advanced transports to perform many I O operations directly on the SAN rather than over the LAN This improves performance and saves network bandwidth VDDK and VADP Compared The Virtual Disk Development Kit VDDK includes a set of C library routines for manipulating virtual disk VixDiskLib and for mounting virtual disk partitions VixMntapi The VDDK focuses on efficient access and transfer of data on virtual disk storage The vSphere Storage APIs for Data Protection VADP is a marketing term for a subset of the vSphere API that enables backup and restore applications The snapshot based VADP framework allows efficient off host centralized backup of virtual machine storage After taking a snapshot to quiesce virtual disk software can then back up storage using VDDK library routines The vSphere API is an XML based Web service that provides the interfaces for vCenter Server management of virtual machines running on ESX ESXi hosts Developers need both VDDK and VADP to write data protection software VADP is presented in Chapter 7 Designing vSphere Backup Solutions
61. Handle appGlobals startSector i 1 buf CHECK_AND_THROWCvixError str buf if pos str findC Vmware 0 str replace pos 5 VMware buf str vixError VixDiskLib_Write disk Handle appGlobals startSector i 1 buf CHECK_AND_THROWCvixError Reading and Writing Remote Disk The DoEdit function is similar for remote managed virtual disk on ESX ESXi hosts but beforehand you must call VixDiskLib_Connect with authentication credentials instead of passing NULL parameters if CappGlobals isRemote cnxParams vmxSpec NULL cnxParams serverName appGlobals host cnxParams credType VIXDISKLIB_CRED_UID cnxParams creds uid userName appGlobals userName cnxParams creds uid password appGlobals password cnxParams port appGlobals port VixError vixError VixDiskLib_Init 1 NULL NULL NULL NULL CHECK_AND_THROW vixError vixError VixDiskLib_Connect amp cnxParams amp appGlobals connection Deleting a Disk Unlink The function to delete virtual disk files is VixDiskLib_Unlink It takes two arguments a connection and a VMDK filename vixError VixDiskLib_Unlink appGlobals connection appGlobals diskPath Effects of Deleting a Virtual Disk When you delete a VMDK you lose all the information it contained In most cases the host operating system prevents you from doing this when a virtual machine is running However if you delete a VMDK with its virtual machine
62. P For VDDK it describes how to develop software using a virtual disk library that provides a set of system call style interfaces for managing virtual disks For VADP it describes how to write backup and restore software for vSphere To view this version or previous versions of this book and other public VMware API and SDK documentation go to http www vmware com support pubs sdk_pubs html Revision History Table 1 summarizes the significant changes in each version of this guide Table 1 Revision History Revision Description 2014 04 08 VDDK 5 5 1 supports GPT Snapshot quiesce and memory are incompatible Describe VMDK version 3 2013 11 08 Fixed several errors involving roles and licensing physical or virtual proxy and log level 2013 10 14 Corrections regarding 32 bit Windows and PackageCode Removed Reparent and Combine APIs 2013 09 22 Final version for the vSphere 5 5 release with new chapter on vApp backup for vCloud Director 2012 12 21 Bug fix version of the vSphere 5 1 manual numeric change ID policy mount restrictions 2012 10 05 Final version of this manual for the vSphere 5 1 release 2011 11 18 Bug fix version for 4Q 2011 refresh of the VMware vSphere Documentation Center 2011 08 22 Final version for the VDDK 5 0 release subsuming Designing Backup Solutions technical note 2010 10 12 Bug fix revision for the VDDK 1 2 1 release 2010 08 05 Version for vSphere 4 1 and the VDDK 1 2 public
63. S based storage arrays SAS means serial attached SCSI VMware vSAN a network based storage solution with direct attached disks does not support SAN transport Because vSAN uses modes and methods that are incompatible with SAN transport if the virtual disk library detects the presence of vSAN it disables SAN mode Other advanced transports do work HotAdd Transport HotAdd is a VMware feature where devices can be added hot while a virtual machine is running Besides SCSI disk virtual machines can add additional CPUs and memory capacity If backup software runs in a virtual appliance it can take a snapshot and create a linked clone of the target virtual machine then attach and read the linked clone s virtual disks for backup This involves a SCSI HotAdd on the ESXi host where the target VM and backup proxy are running Virtual disks of the linked clone are HotAdded to the backup proxy The target virtual machine continues to run during backup VixTransport handles the temporary linked clone and hot attachment of virtual disks VixDiskLib opens and reads the HotAdded disks as a whole disk VMDK virtual disk on the local host This strategy works only on virtual machines with SCSI disks and is not supported for backing up virtual IDE disks HotAdd transport also works with virtual machines stored on NFS partitions HotAdd is a good way to get virtual disk data from a virtual machine to a backup appliance or backup proxy for sen
64. S metadata might also contain information such as disk label LUN or partition layout number of links file attributes locks and so forth Metadata also describes encapsulation of raw disk mapping RDM storage if applicable Get Metadata Table from Disk VixDiskLib_GetMetadataKeys retrieves all existing keys from the metadata of a virtual disk but not the key values Use this in conjunction with VixDiskLib_ReadMetadata vixError VixDiskLib_GetMetadataKeys disk Handle amp buf 0 requiredLen NULL Here is an example of a simple metadata table Uuid is the universally unique identifier for the virtual disk adapterType buslogic geometry sectors 32 geometry heads 64 geometry cylinders 100 uuid 60 00 C2 93 7b a0 3a 03 9f 22 56 c5 29 93 b7 27 Write Metadata Table to Disk VixDiskLib_WriteMetadata updates virtual disk metadata with the given key value pair If the key value pair is new it gets added If the key already exists its value is updated A key can be zeroed but not deleted vixError VixDiskLib_WriteMetadata disk Handle appGlobals metaKey appGlobals metaVa1 Cloning a Virtual Disk Compute Space Needed for Clone This function computes the space required in bytes to clone a virtual disk after possible format conversion vixError VixDiskLib_SpaceNeededForClone child Handle Q VIXDISKLIB_DISK_VMFS_FLAT amp spaceReq VMware Inc 31 Virtual Disk Programming Guide VixDiskLib_S
65. Section GET https vCloud api vapp id networkConnectionSection GET https vCloud api vapp id runtimeInfoSection Preventing Updates to a vApp During Backup or Restore While you are backing up or restoring a vApp you need to prevent updates to the vApp configuration and metadata so that the vApp remains internally consistent To prevent updates during the backup restore process the vCloud API allows the vApp to be placed in maintenance mode which rejects any new updates to the configuration and metadata The backup software must select maintenance mode for the vApp before starting backup or restore operations and deselect maintenance mode for the vApp after the operations are completed Example 8 12 shows how to select and deselect maintenance mode for a vApp VMware Inc Backing Up vApps in vCloud Director Example 8 12 Protecting a vApp with Maintenance Mode using com vmware vclLoud sdk using com vmware vcLloud api rest schema VApp vapp VApp utility class from vCloud SDK Identify vApp vapp EnablLeMaintenance Enter maintenance mode Perform backup restore here vapp DisableMaintenance Exit maintenance mode Example 8 13 shows the corresponding REST API calls to select and deselect maintenance mode for a vApp Example 8 13 REST API Calls To Protect a vApp with Maintenance Mode POST https vCloud api vapp id action enterMaintenancemode POST https vCloud api vapp id action exitMaintena
66. VMware Inc Designing vSphere Backup Solutions Creating a New Virtual Machine The process of building a virtual machine from backup data involves the following steps 1 Create the virtual machine To create a new virtual machine you use the information about virtual machine configuration that you derived and saved during the backup process You might allow users of restore software an opportunity to rename the virtual machine during recovery in case they want to clone or move the virtual machine Also you might consider offering them an opportunity to change virtual machine layout for instance storing virtual disks on a different datastore Creating the virtual disks is also done at the time when you create the virtual machine This process is fairly complicated See the section Low Level Backup Procedures on page 64 for details 2 Restore the virtual disk data This process is similar to restoring the contents of virtual disks Step 3 under Restoring an Existing Virtual Machine to a Previous State on page 62 with the following exception you must call the VixDiskLib_WriteMetadata function to write all the disk configuration key value data into the virtual disk before restoring any backed up data to the virtual disk Then call VixDiskLib_Write to restore the virtual disk data as described in Step 3 above 3 Power on the virtual machine Accessing Files on Virtual Disks It might be necessary for a backup application to
67. Virtual Disk Programming Guide vSphere Storage APIs for Data Protection VADP 5 5 Virtual Disk Development Kit VDDK 5 5 This document supports the version of each product listed and supports all subsequent versions until the document is replaced by a new edition To check for more recent editions of this document see http www vmware com support pubs EN 001 129 04 vmware Virtual Disk Programming Guide You can find the most up to date technical documentation on the VMware Web site at http www vmware com support The VMware Web site also provides the latest product updates If you have comments about this documentation submit your feedback to docfeedback vmware com Copyright 2008 2014 VMware Inc All rights reserved This product is protected by U S and international copyright and intellectual property laws VMware products are covered by one or more patents listed at http www vmware com go patents VMware is a registered trademark or trademark of VMware Inc in the United States and or other jurisdictions All other marks and names mentioned herein may be trademarks of their respective companies VMware Inc 3401 Hillview Ave Palo Alto CA 94304 www vmware com 2 VMware Inc Contents About This Book 9 1 Introduction to the Virtual Disk API 11 About the Virtual Disk API 11 VDDK Components 11 Virtual Disk Library 12 Disk Mount Library 12 Virtual Disk Utilities 12 Backup and Restore on vSphere
68. VixMntapi_FreeVoLumeHandles VixVoLlumeHandle volumeHandles Parameter m volumeHandles in Volume handle to be freed VixMntapi_GetOsInfo Retrieves information about the default operating system in the disk set To get operating system information VixMntapi_GetOsInfo requires the system and boot volumes to be already mounted It does not dismount the system volume at the end of this function Your application should be prepared to handle the volume already mounted error gracefully This function is effective only when used with operating systems of the same type For instance a VixMntapi program running on Windows can provide information about the VMDK of a Windows virtual machine but not about the VMDK of a Linux virtual machine VixError VixMntapi_GetOsInfo VixDiskSetHandle diskSet VixOsInfo info Parameters m diskSet in Handle to an open disk set m info out OS information to be filled in VMware Inc Virtual Disk Mount API VixMntapi_FreeOsInfo Frees memory allocated by VixMntapi_GetOsInfo void VixMntapi_FreeOsInfo VixOsInfo info Parameter m info in OS info to be freed VixMntapi_MountVolume Mounts the volume After mounting the volume use VixMntapi_GetVolumeInfo to obtain the path to the mounted volume This mount call locks the source disks until you call VixMntapi_DismountVoLume The VixMntapi_MountVolume function cannot mount Linux swap or extended partitions V
69. Web Services API 55 Virus Scan All Managed Disk 56 Read and Write VMDK with vSphere WS API 56 7 Designing vSphere Backup Solutions 57 Design and Implementation Overview 57 The Backup Process 57 Communicating With the Server 58 Information Containers as Managed Objects 58 More About Managed Objects 58 Managed Object References 59 Unique ID for a Different vCenter 59 Gathering Status and Configuration Information 59 PropertyCollector Data 59 Useful Property Information 60 Doing a Backup Operation 60 Prerequisites for Backup 60 Create a Temporary Snapshot on the Target Virtual Machine 60 Changed Block Tracking 61 Extract Backup Data from the Target Virtual Machine 61 Delete the Temporary Snapshot 61 The Restore Process 61 Doing a Restore Operation 62 Prerequisites for Restore 62 Restoring an Existing Virtual Machine to a Previous State 62 Creating a New Virtual Machine 63 Accessing Files on Virtual Disks 63 More VADP Details 64 Low Level Backup Procedures 64 Communicating with the Server 64 The PropertyCollector 64 PropertyCollector Arguments 64 Getting the Data from the PropertyCollector 67 Identifying Virtual Disks for Backup and Restore 68 Creating aSnapshot 69 Backing Up a Virtual Disk 69 Deleting a Snapshot 70 Changed Block Tracking on Virtual Disks 70 Enabling Changed Block Tracking 71 Gathering Changed Block Information 71 Troubleshooting 73 Limitations on Changed Block Tracking 73 Checking for Namespace 73 Low Level Restore P
70. a Red Hat Enterprise Linux client For an ESX ESXi host path to disk is often something like datastore1 followed by the virtual machine name and the VMDK filename vix diskLib sample info host esx5 user root password secret datastore1 RHEL6 RHEL6 vmdk Disk datastore1 RHEL6 RHEL6 vmdk is open using transport mode nbd capacity 4194304 sectors number of links 1 adapter type LsiLogic SCSI BIOS geometry 0 0 0 physical geometry 261 255 63 Transport modes supported by vixDiskLib file nbdssl nbd VMware Inc Virtual Disk API Sample Code If you multiply physical geometry numbers 261 cylinders 255 heads per cylinder 63 sectors per head the result is a capacity of 4192965 sectors although the first line says 4194304 A small discrepancy is possible due to rounding In general you get at least the capacity that you requested The number of links specifies the separation of a child from its original parent in the disk chain redo logs starting at one The parent has one link its child has two links the grandchild has three links and so forth DoCreate This procedure calls VixDiskLib_Create to allocate virtual disk Adapter type is SCSI unless specified as IDE on the command line Size is 100MB unless set by cap on the command line Because the sector size is 512 bytes the code multiplies appGlobals mbsize by 2048 instead of 1024 Type is always monolithic sparse and Workstation 5 In a production appl
71. achine you first need to create a snapshot Once the snapshot is created you then need to identify the virtual disks associated with this snapshot A virtual machine might have multiple snapshots associated with it Each snapshot has a virtual copy of the virtual disks for the virtual machine These copies are named with the base name of the disk and a unique decimal number appended to the name The format of the number is a hyphen character followed by a 6 digit zero filled number An example a disk copy name might be mydisk NNNNNN vmdk where NNNNNN would be some number like 000032 The vSphere API identifies virtual disk files by prefixing the datastore name onto the file system pathname and the filename StorageN myvmname mydisk NNNNNN vmdk The name in square brackets corresponds to the short name of the datastore that contains this virtual disk while the remainder of the path string represents the location relative to the root of this datastore To get the name and characteristics of a virtual disk file you use the PropertyCollector to select the property config hardware device from a VirtualMachine managed object This returns an array of virtual devices associated with a VirtualMachine or Snapshot You must scan this list of devices to extract the list of virtual disks All that is necessary is to see if each VirtualDevice entry extends to VirtualDisk When you find such an entry examine the BackingInfo property You must extend
72. ackup and restore operations are performed using the VMware vStorage APIs for Data Protection VADP VMware vCloud Director uses one or more vCenter servers to manage virtualized resources At the same time it manages the vCloud feature of multi tenancy by maintaining metadata related to various tenant artifacts such as vApp users networks storage and so on VMware Inc Backing Up vApps in vCloud Director When a system administrator chooses to back up a vApp certain vApp metadata must be retrieved from vCloud Director The metadata includes general information about the vApp name description virtual machine descriptions networking information organization network connectivity external network connectivity user information lease and quota This information becomes particularly important when restoring the vApp in addition to the names of virtual disk files and vmx files typically retrieved from vSphere using the VADP The Backup Process The backup process requires the backup restore software to collect and store information both from vCloud Director and from vSphere This process assumes that you use vCloud Director system administrator credentials to connect to vCloud Director System administrator credentials allow the software to access vApps belonging to any Organization and to access all the necessary information about a vApp and associated vCloud constructs A vApp in vCloud Director can comprise one or more virtual
73. ackup software should ignore independent disks those not capable of snapshots These virtual disks are unsuitable for backup They throw an error if a snapshot is attempted on them To back up thick disk the proxy s datastore must have at least as much free space as the maximum configured disk size for the backed up virtual machine Thin provisioned disk is often faster to back up With SSL certificate checking in vSphere 5 1 and after DNS services must be configured in the backup proxy otherwise SSL_Verify will fail with the no host found error To back up thick disk the proxy s datastore must have at least as much free space as the maximum configured disk size for the backed up virtual machine Thick disk takes up all its allocated size in the datastore To save space you can choose thin provisioned disk which consumes only the space actually containing data If you do a full backup of lazy zeroed thick disk with CBT disabled the software reads all sectors converting data in empty lazy zero sectors to actual zeros Upon restore this full backup data will produce eager zeroed thick disk This is one reason why VMware recommends enabling CBT before the first snapshot Backup and Restore of Thin Provisioned Disk Thin provisioned virtual disk is created on first write So the first time write to thin provisioned disk involves extra overhead compared to thick disk whether using NBD NBDSSL or HotAdd This is due to block allocation
74. act using QueryChangedDiskAreas from the snapshot s virtual disk When you back up a snapshot for the first time ChangeId should be unset or unsaved indicating that a baseline full backup is required If you have a saved ChangeTId it identifies the last time a backup was taken and tells the changed block tracking logic to identify changes that have occurred since the time indicated by the saved Changeld There are two ways to get this baseline backup 1 Directly save the entire contents of the virtual disk 2 Provide the special ChangeId star The star indicates that QueryChangedDiskAreas should return only active portions of the virtual disk For both thin provisioned sparse virtual disks and for ordinary virtual disks this causes a substantial reduction in the amount of data to save Woe To summarize changeID is an identifier for a time in the past It can be star to identify all allocated areas of virtual disk ignoring unallocated areas of sparse disk or it could be a changeId string saved at the time when a pre backup snapshot was taken It only makes sense to use the special ChangeId when no previous Changeld exists If a previous ChangeId does exist then QueryChangedDiskAreas returns the disk sectors that changed since the new ChangeId was collected Table 7 3 shows the algorithm Table 7 3 Use of Change ID for Changed Block Tracking New Change ID Old Change ID Used for Query Result change 0 none 5 All in
75. acts information useful for manipulating a service 1 Create the service instance moRef ManagedObjectReference svcRef new ManagedObjectReference svcRef setType ServiceInstance svcRef setValue ServiceInstance 2 Locate the service VimServiceLocator Locator new VimServiceLocator locator setMaintainSession true VimPortType serviceConnection locator getVimPort https your_server sdk 3 Log in to the session manager ServiceInstanceContent serviceContent serviceConnection retrieveContent svcRef ManagedObjectReference sessionManager serviceInstance getSessionManager UserSession us serviceConnection login sessionManager username password null The PropertyCollector The PropertyCollector is used in this section to apply the above details to the backup task PropertyCollector Arguments The PropertyCol lector uses two relatively complicated argument structures As was mentioned in PropertyCollector Data on page 59 these arguments are PropertySpec and ObjectSpec PropertySpec is a list of the information desired and ObjectSpec is a list of instructions indicating where to find the information In theory you could directly address an object using its moRef In that case an ObjectSpec can be very simple However getting the initial moRef can be a challenge when a complicated ObjectSpec is required To formulate a complex ObjectSpec you need to understand the structure of the available d
76. age 21 the preferred syntax for vmxSpec is as follows m Managed object reference of the virtual machine an opaque object that you obtain programmatically using the PropertyCollector managed object moRef lt moref of vm gt The moRef of a virtual machine or disk snapshot on an ESX ESXi host is likely different than the moRef of the same virtual machine or disk snapshot as managed by vCenter Server Here are two example moRef specifications one for ESXi and one for vCenter Server both referring to the same snapshot moref 153 moref 271 VMware Inc 29 Virtual Disk Programming Guide Disk Operations 30 These functions create open read write query and close virtual disk Create a New Hosted Disk VixDiskLib_Create locally creates a new virtual disk after being connected to the host In createParams you must specify the disk type adapter hardware version and capacity as a number of sectors This function supports hosted disk For managed disk first create a hosted type virtual disk then use VixDiskLib_Clone to convert the virtual disk to managed disk vixError VixDiskLib_Create appGlobals connection appGlobals diskPath amp createParams NULL NULL Currently VixDiskLib_Create enforces a 4GB limit for virtual disks on FAT32 and FAT file systems a 16TB 54KB hex FFFFFFF0000 limit on NTFS file systems and a 264 1 limit more than an exabyte on ReFS and exFAT file systems VMDK files gt 2TB are
77. age 84 For an overview of backup and help designing your top level program structure read the first section below For details about implementing low level backup code read the remaining sections You should be familiar with virtual machines snapshots ESXi vCenter and Java Design and Implementation Overview On vSphere backups are usually done by taking a snapshot to efficiency obtain a static image of the virtual machine Snapshots are a view of a virtual machine at a certain point in time and enable quick and clean backup operation Snapshots also provide an incremental backup mechanism called changed block tracking To back up virtual machines on vSphere VMware recommends a two language solution First use Java to code the backup program that contacts the host takes a temporary snapshot records virtual machine configuration and later deletes the snapshot Then use C or C to code the VDDK program that transfers virtual disk data from the snapshot to backup media For restore VMware recommends a two language solution First use Java to code the program that instructs the virtual machine to halt or re creates the target virtual machine from recorded configuration Then use C or C to code the VDDK program that transfers saved data from backup media to virtual disk The Backup Process These are the high level steps to back up a virtual machine running in vSphere 1 Connect to the ESXi host containing the virtual machine target
78. aged disk follow these steps 1 Find all instances of VixDiskLib_Connect and change them to VixDiskLib_ConnectEx The vixDiskLib sample program was extended to use VixDiskLib_ConnectEx with the mod option 2 Likewise change VixDiskLib_Init to VixDiskLib_InitEx and be sure to call it only once 3 Disable virtual machine relocation with the VixDiskLib_PrepareForAccess call 4 Add parameters in the middle a TRUE for high performance read only access FALSE for read write access b Snapshot moRef if applicable c NULL to accept transport method defaults recommended 5 Re enable virtual machine relocation with the VixDiskLib_EndAccess call 6 Find VixDiskLib_Disconnect near the end of program and for safety add a VixDiskLib_CLeanup call immediately afterwards 7 Compile with the new flexible transport enabled version of VixDiskLib The advanced transport functions are useful for backing up or restoring data on virtual disks managed by VMware vSphere Backup is based on the snapshot mechanism which provides a data view at a certain point in time and allows access to quiescent data on the parent disk while the child disk continues changing Algorithm for vSphere Backup A typical backup application follows this algorithm m Preferably through vCenter Server contact the ESX ESXi host and discover the target virtual machine m Ask the ESX ESXi host to take a snapshot of the target virtual machine m Using the vSphere API Prope
79. ains Backup Writers Components details This is generated by the VSS mechanism after backup By cross verifying these backup writers components details according to Microsoft VSS documentation you can verify if a particular application consistent quiescing was completed successfully or not VMware Tools is responsible for initiating the VSS snapshot process as the VSS requester Users send a request to hostd for a quiesced snapshot of the virtual machine The request goes from hostd to the VMware Tools for a VSS snapshot Once the VSS snapshot is completed with success or error it communicates back to the hostd process The VSS snapshot is created with the vss manifest file or without this file in the error case The VSS requester sets up the overall configuration for the backup operation including whether the snapshot should be performed in component mode or not whether to take a snapshot with a bootable system state and whether the snapshot should be for a full copy or differential backup If application consistent quiescing is performed then all writers and all components are involved VMware Tools initiates VSS quiescing using VSS_CTX_BACKUP context for application quiescing capable guests with backup state set to select components backup bootable system state with backup type VSS_BT_COPY and no partial file support and VSS_CTX_FILE_SHARE_BACKUP for file system quiescing capable guests Currently there is no way to control any of these param
80. alMachine MORef ResourcePool vApp ComputeResource Provider vDC vDC Datacenter Org VMware Inc 99 Virtual Disk Programming Guide 100 The vCloud API describes the mapping in terms of XML elements shown in Example 8 14 The box in the example highlights XML data that maps a virtual machine from vCloud Director to vSphere The MoRef of the virtual machine is in bold type The object type is shown as VIRTUAL_MACHINE Example 8 14 XML Mapping a Virtual Machine URL to a MoRef lt Vm needsCustomization false deployed false status 3 name RedHat6 id urn vcLloud vm 487ba71 05 8a 47a9 9e9a def458c63fd5 type appLlication vnd vmware vcloud vm xmL href https 10 20 140 167 api vApp vm f487ba71 058a 47a9 9e9a def458c63fd5 gt lt VCloudExtension required false gt lt vmext VmVimInfo gt lt vmext VmVimObjectRef gt lt vmext VimServerRef type application vnd vmware admin vmwvirtualcenter xmL name dao_w2k8_vc href https 10 20 140 167 api admin extension vimServer e7026985 19f6 4b9a 9d0d 588629e63347 gt lt vmext MoRef gt vm 63 lt vmext MoRef gt lt vmext Vim0bjectType gt VIRTUAL_MACHINE lt vmext VimObjectType gt lt vmext VmVim0bjectRef gt lt vmext DatastoreVim0bjectRef gt lt vmext VimServerRef type appLlication vnd vmware admin vmwvirtualcenter xmL name dao_w2k8_vc href https 10 20 140 167 api admin extension vimServer e7026985 19fF6
81. alMachineConfigInfo contains the cpuFeatureMask field which is an array of HostCpuIdInfo The array entries must be converted to ArrayUpdateSpec entries containing the VirtualMachineCpuIdInfoSpec along with the operation field which must contain the value ArrayUpdateOperation add The VirtualMachineCpuIdInfoSpec also contains a HostCpuIdInfo array that you can copy from the cpuFeatureMask array in VirtualMachineConfigInfo These items are not reflected in the sample code Everything else can be copied intact from VirtualMachineConfigInfo data To summarize when creating a virtual machine in which to restore virtual disk m Exclude default devices and VirtualController device from the VirtualMachineConfigSpec m Set the parent virtual disk backing information VirtualDisk FlatVer2BackingInfo to null m Convert HostCpulIdInfo array entries to ArrayUpdateSpec insert ArrayUpdateOperation add and copy the HostCpuIdInfo array from cpuFeatureMask into VirtualLMachineConfigInfo Editing or Deleting a Device If backup clients want to edit or delete a device they must use the server provided key when referring to an existing device For the definition of key see Creating a Virtual Machine on page 74 For example see the key and controllerKey for CDROM in the source code on page 75 The key uniquely identifies a device while the controllerKey uniquely identifies the controller where it is connected Restoring Virtual Disk Data
82. alid and the child handle represents the combined disk chain of redo logs vixError VixDiskLib_Attach parent HandleQ child Handle For example suppose you want to access the older disk image recorded by Child1 Attach the handle of new Child1a to Child1 which provides Child1a s parent handle as shown in Figure 4 2 It is now permissible to open read and write the Child1a virtual disk The parent child disk chain is efficient in terms of storage space because the child VMDK records only the sectors that changed since the last VixDiskLib_CreateChild The parent child disk chain also provides a redo mechanism permitting programmatic access to any generation with VixDiskLib_Attach Figure 4 2 Child Disks Created from Parent Virtual Machine Writes Here v Child3 vm vmdk vm 001 vmdk Child2 vm vmdk vm 002 vmdk 7 Attach Child1a vmdk Child1 vm vmdk vm 001 vmdk Parent vm vmdk vm flat vmdk Physical Disk Opening in a Chain With parent base disk B and children C0 C1 and C2 opening C2 gives you the contents of B C0 C1 C2 not really addition linked data sectors while opening C1 gives you the contents of B CO C1 A better solution than recording base disks and which children are descended from which is changed block tracking QueryChangedDiskAreas in the vSphere API See Algorithm for vS
83. arameters m Boolean indicating TRUE for read only access often faster or FALSE for read write access If connecting read only later calls to VixDiskLib_Open are always read only regardless of the openF lags setting m Managed object reference MoRef of the snapshot to access with this connection This is required for most transport methods SAN HotAdd NBDSSL and to access a powered on virtual machine You must also specify the associated vmxSpec property in connectParams When connecting directly to an ESX ESXi host provide the ESX ESXi MoRef When connecting through vCenter Server pass the vSphere MoRef which differs m Preferred transport method or NULL to accept defaults If you specify SAN as the only transport and SAN is not available VixDiskLib_ConnectEx does not fail but the first VixDiskLib_Open call will fail VixDiskLibConnectParams cnxParams 0 if appGlobals isRemote cnxParams vmName vmxSpec cnxParams serverName hostName cnxParams credType VIXDISKLIB_CRED_UID cnxParams creds uid userName userName cnxParams creds uid password password cnxParams port port VixError vixError VixDiskLib_ConnectEx amp cnxParams TRUE snapshot 47 NULL amp connection Even when a program calls VixDiskLib_ConnectEx with NULL parameter to accept the default transport mode SAN is selected as the preferred mode if SAN storage is available from the ESX ESXi host Then if the program opens a vi
84. as no option for mounting a read only file system In Figure 6 1 the gray circle represents a virtual disk that must remain read only because it has children In this example you want the Windows 2000 virtual machine to use that virtual disk rather than the newer ones C1 and C2 Create new child disk RO attach to the gray virtual disk as parent and mount RO as the mostly empty read only virtual disk of the Windows 2000 guest OS VMware Inc 53 Virtual Disk Programming Guide Figure 6 1 Attaching Virtual Read Write Disk for Windows 2000 Windows 2000 RDM Disks and Virtual BIOS 54 This section outlines low level procedures for restoring raw device mapping RDM disks and NVRAM Restoring RDM Disks Backing up and restoring RDM disks presents unusual challenges The original backed up RDM configuration might not apply and is probably not appropriate if users restore m A virtual machine to a different host or datastore m A virtual machine that was deleted when its originally mapped RDM was also deleted or the containing LUN was repurposed and rewritten m The RDM to a different virtual machine even if that virtual machine is on the same host and datastore Users might do this to access files on the disk or to test a restore When performing a proxy backup of an RDM disk you must present the same LUN ID to both the ESXi host and the proxy server This restriction does not apply to VMFS disk because the virtual disk
85. ase you can use the disk mount API vixMntapi for local and remote mounting of virtual disks The vmware mount command does this too VixMntapi involves a separate library for loading m The VixMntapi Library on page 103 m Programming with VixMntapi on page 108 m Sample VixMntapi Code on page 109 m Restrictions on Virtual Disk Mount on page 109 y CAUTION The vixMntapi library for Windows supports advanced transport for SAN and HotAdd but for Linux the vixMntapi library supports only local and LAN transport file nbd nbdss1 The VixMntapi Library The VixMntapi library supports guest operating systems on multiple platforms On POSIX systems it requires FUSE mount available on recent Linux systems and freely available on the SourceForge Web site Definitions are contained in the following header file installed in the same directory as vixDiskLib h include vixMntapi h Types and Structures This section summarizes the important types and structures Operating System Information The VixOsInfo structure encapsulates the following information m Family of the guest operating system VixOsFamilLy one of the following Windows NT based Linux Netware Solaris FreeBSD OS 2 Mac OS X Darwin m Major version and minor version of the operating system m Whether it is 64 bit or 32 bit m Vendor and edition of the operating system m Location where the operating system is installed VMware
86. at load the libraries Libss1 so 0 9 8 and libcrypto so 0 9 8 do the following 1 Attempt to load them from the environment s LD_LIBRARY_PATH location 2 Next attempt to load them from the directory where LibvixDiskLib so is located 3 Next attempt to load them from the directory where the executable is located 4 Failing that exit with an error VMware Inc 111 Virtual Disk Programming Guide On install VDDK creates the directory usr lib vimware vix disklib populated with 64 bit executables and libraries placed into subdirectories bin64 and 1i1b64 On determining the OS type VDDK copies the vixDiskLib and vixMntapi libraries into usr 17b It does not copy libss1 so 0 9 8 or Libcrypto so 0 9 8 into usr 1Lib On execution the root user normally has no LD_LIBRARY_PATH and usr lib is ahead of opt vmware 1ib in the path Running the Ldd command can help diagnose where a program is getting LibvixDiskLib soand other libraries The opt vmware 1ib directory is neither created nor updated by the VDDK install script If you see the error Failed to load library libcrypto so 0 9 8 there are several solutions Set or reset the LD_LIBRARY_PATH environment so it contains one of the directories above 1i1b64 and possibly bin64 before it contains usr 1ib Change the symbolic link in opt vmware 11b or elsewhere so it points to the directory above 11b64 Copy the libss1 and libcrypto libraries from usr 1ib vmware vix disk
87. at supports these attributes it supports them The following volume types are supported Simple Spanned Striped RAID 0 and Mirrored RAID 1 RAID 5 parity striped is not supported You must open a disk set read write to obtain the OS information for dynamic volume types including LDM and LVM If you cannot open a base disk read write create a child disk in front and open it read write In a multi boot setup only the first entry 0 is opened The order of mounting is important For instance mount top level directories before subdirectories and drives with dependencies after drives that they depend on Mount points are not enumerated nor are they restored When you mount one volume the other volumes are not implicitly mounted also Read Only Mount on Linux Linux vixMntapi does not support read only access It is explicitly disabled in the code due to journal replay requirements when mounting ext3 and later file systems To mount a disk read only you must either mount the virtual disk of a powered off virtual machine or mount the snapshot of a powered on virtual machine The VixMntapi library can emulate mounting disks read only as in the Linux procedure below A similar procedure with different temporary filename could be used on Windows To mount disks read only 1 Open the base disk with VixDiskLib_Open passing the flag VIXDISKLIB_FLAG_OPEN_READ_ONLY 2 Call VixDiskLib_CreateChild to create a child snapshot of the base d
88. atVer2BackingInfo vim vm device VirtualDevice VirtualDiskSparseVer2BackingInfo vim vm device VirtualDevice VirtualLDiskRawDiskMappingVer1BackingInfo vim vm device VirtualDevice VirtuaLDiskRawDiskVer2BackingInfo Information returned by the QueryChangedDiskAreas method is a DiskChangeInfo data object containing an array of DiskChangeInfo DiskChangeExtent items that enumerate the start offset and length of various disk areas that changed and the length and start offset of the entire disk area covered by DiskChangeInfo When using QueryChangedDiskAreas to gather information about snapshots enable change tracking before taking a snapshot Attempts to collect information about changes that occurred before change tracking was enabled result in a FileFault error Enabling change tracking provides the additional benefit of saving space because it enables backup of only information that has changed If change tracking is not enabled the entire virtual machine must be backed up each time rather than incrementally Changed block tracking is supported whenever the I O operations are processed by the ESXi storage stack m Fora virtual disk stored on VMFS no matter what backs the VMFS volume SAN or local disk m Fora virtual disk stored on NFS m For an RDM in virtual compatibility mode When I O operations are not processed by the ESXi storage stack changed block tracking is not usable m For an RDM in physical compatibility mode m A disk that is
89. ata This is complicated by the fact that an ObjectSpec can contain recursive elements Understanding an ObjectSpec An ObjectSpec is a list of Obj ectSpec elements each specifying an object type and giving a selection spec for the object More About Managed Objects on page 58 describes five types of managed objects Folder Datacenter ComputeResource ResourcePool and VirtualMachine VirtualApp vApp isa sixth type You can traverse objects because one managed object leads to another m Folder One of the items contained in the Folder is called childEntity which is a list of moRefs that can contain one of the five managed object types A Folder can be parent to any of these managed objects m Datacenter This managed object has two items that lead to other managed objects m hostFolder A moRef to a Folder containing a list of ComputeResources comprising a Datacenter m vmFolder A moRef to a Folder containing the VirtualMachines that are part of the Datacenter If it is your objective to duplicate the display seen in a vSphere Client GUI then this Folder is of limited use because it does not describe the ResourcePool that is the parent of a virtual machine VMware Inc Designing vSphere Backup Solutions ComputeResource A ComputeResource is basically hardware A ComputeResource can comprise multiple systems The hardware represents resources that can be used to implement a VirtualMachine object Vir
90. ault all VSS writers are involved but a mechanism for excluding writers exists see the VMware KB article 1031200 For help troubleshooting see KB article 1007696 VMware Inc Backing Up vApps in vCloud Director This chapter introduces developers to the concepts and procedures for creating backup and restore solutions for vCloud Director This chapter is divided into the following main sections Introduction to Tenant vApps on page 87 Conceptual Overview on page 88 Use Cases Overview on page 90 vCloud API Operations on page 92 Conclusion on page 102 Introduction to Tenant vApps The vApp is a management construct that encapsulates one or more virtual machines running in the vSphere environment The tenant vApp is a higher level construct that allows vCloud Director to manage vApps and virtual machines running in a multi tenant datacenter or in a multi tenant cloud based on vSphere Figure 1 shows the objects within a single organization that you can access with the vCloud API VMware Inc Figure 1 vCloud API Object Taxonomy vDC2 vApp implan Ls 87 Virtual Disk Programming Guide Multi tenant and self service capabilities of vCloud Director provide multiple levels of protection for a vApp A service provider can offer vApp protection at the system level the tenant level or the end user level managed by the system administrator Organization administrator and end user res
91. ays logs into the System organization When Administrator System is used as the user name for the API Administrator is the login name and System is the System Organization name Using system administrator privileges to connect to vCloud Director also allows the backup restore software to access additional information relating a vApp to the corresponding resources in vSphere This is described in Inventory Access on page 92 Example 8 1 shows how to log in using C with the vCloud SDK for NET After logging in the code shows how to access Organization data Example 8 1 vCloud Director login code sample using Administrator System lt password gt using com vmware vclLoud sdk using com vmware vcLloud api rest schema public static vCloudClient client null client new vCloudClient vCloudURL com vmware vcloud sdk constants Version V1_5 client Login username password Get references to all Organizations Dictionary lt string ReferenceType gt organizationsMap client GetOrgRefsByName Get reference to a specific Organization string orgName Org1 ReferenceType orgRef client GetOrgRefByName orgName Convert Organization reference to Organization object Organization org Organization GetOrganizationByReference client orgRef Inventory Access In general you locate a desired vApp for backup in the context of a given Organization and VDC To locate a vApp that you want to back up you first
92. backup server with access to SAN storage Fibre Channel iSCSI or SAS connected containing the virtual disks to be accessed As shown in Figure 3 1 this method is efficient because no data needs to be transferred through the production ESX ESXi host A SAN backup proxy must be a physical machine If it has optical media or tape drive connected backups can be made entirely LAN free Figure 3 1 SAN Transport Mode for Virtual Disk ESX host backup server virtual machine VMware Tools application Virtual Disk Fibre Channel SAN API storage LAN Fibre Channel iSCSI storage VMware Inc 23 Virtual Disk Programming Guide 24 In SAN transport mode the virtual disk library obtains information from an ESX ESXi host about the layout of VMFS LUNs and using this information reads data directly from the storage LUN where a virtual disk resides This is the fastest transport method for software deployed on SAN connected ESX ESXi hosts SAN storage devices can contain SATA drives but currently there are no SATA connected SAN devices on the VMware hardware compatibility list In general SAN transport works with any storage device that appears at the driver level as a LUN as opposed to a file system such as NTFS or EXT SAN mode must be able to access the LUN as a raw device The real key is whether the device behaves like a direct raw connection to the underlying LUN SAN transport is supported in Fibre Channel iSCSI and SA
93. bus assignment for the controller must be the next available bus number in sequence Also note that VMware implicitly adds a SCSI controller to a VM if a bus disk assignment for a newly created virtual disk refers to a controller that does not yet exist For instance if disks 0 0 and 0 1 are already in place adding disk 1 0 is fine but adding disk 3 0 breaks the bus ID sequence implicitly creating out of sequence SCSI controller 3 To avoid HotAdd problems you should add virtual disks in numeric sequence To deal with more disks than can fit on a single controller you must add some permanent dummy disks to the proxy VM one on each additional controller that might be needed Adding only the controller does not cause the controller to remain attached to the proxy VM A real VMDK must be added on the controller to keep it attached to the proxy VM Windows Backup Implementations The following sections discuss issues when backing up Windows virtual machines Working with Microsoft Shadow Copy Microsoft Shadow Copy also called Volume Snapshot Service VSS is a Windows Server data backup feature for creating consistent point in time copies of data called shadow copies The type of quiescing used varies depending on the operating system of the backed up virtual machine as shown in Table 7 4 ESX ESXi 4 1 added support for Windows 2008 guests using application level quiescing Table 7 4 Driver Type and Quiescing Mechanisms Used According to
94. c setSelectSet folderTS Attach the TraversalSpec we designed above Understanding a PropertySpec A PropertySpec is a list of individual properties that can be found at places identified by the ObjectSpec and its TraversalSpec Once the PropertyCollector has a moRef it can then return the properties associated with that moRef This can include nested properties Nested properties are properties that can be found inside of properties identified at the top level of the managed object Nested properties are identified by a dot notation An example of nested properties can be drawn from the VirtualMachine managed object A VirtualMachine has the property identified as summary which identifies a VirtualMachineSummary data object The VirtualMachineSummary contains property config which identifies a VirtualMachineConfigSummary data object The VirtualMachineConfigSummary has a property called name which is a string containing the display name of the VirtualMachine You can access this name property using the summary config name string value To address all the properties of the VirtualMachineConfigSummary object you would use the summary config string value The PropertyCollector requires an array of PropertySpec elements Each element includes m Type The type of object that contains the enclosed list of properties m PathSet An array of strings containing names of properties to be returned including nested properties It is nec
95. cause Windows On Windows 64 can run 32 bit programs without alteration VMware provides only 64 bit libraries Disk Mount Library The virtual disk mount library vixMntapi allows programmatic access of virtual disks as if they were mounted disk partitions For more information see Appendix A Virtual Disk Mount API on page 103 The vixMntapi library is packaged in the VDDK with vixDiskLib Virtual Disk Utilities The Virtual Disk Development Kit used to include two command line utilities for managing virtual disk files disk mount and virtual disk manager They were last delivered in the VDDK 5 0 release For more information see the old Disk Mount and Virtual Disk Manager User s Guide still available on the Web Backup and Restore on vSphere The VMware Storage APIs Data Protection VADP is a collection of APIs that are useful for developing or extending backup software so it can protect virtual machines running on ESX ESXi hosts in VMware based datacenters For more information see Chapter 7 Designing vSphere Backup Solutions on page 57 Backup Design for vCloud Director With VMware vCloud the self service capabilities of vCloud Director provide three levels of data protection Backup providers can offer vApp protection at the system level the tenant level or the end user level For information about vCloud data protection see the technical note Backup Design for vCloud Tenant vApps Use Cases for the Virtual Dis
96. ced transport mode you must create a snapshot before restoring virtual machine data This is recommended but not necessary with HotAdd NBDSSL and NBD transport modes 3 Restore contents of the virtual disk s If there were no pre existing snapshots at backup time just the snapshot just created restore only the base disks Restoring disk data requires that you obtain the current names of virtual disks This process is similar to the one described in Extract Backup Data from the Target Virtual Machine on page 61 except in this case you obtain this information directly from the virtual machine and not from a snapshot The target for the saved disk data must be the actual disk name including any sequence number because the current incarnation of a virtual machine may be derived from one or more snapshots Restoring disk data requires use of VixDiskLib The VixDiskLib_Write function opens the virtual disks so your program can write data VixDiskLib functions transfer data to even sector boundaries only and transfer length must be an even multiple of the sector size The virtual disk already exists so it is not necessary to restore the disk configuration information mentioned in Extract Backup Data from the Target Virtual Machine on page 61 4 WithSAN transport mode revert to and delete the snapshot that you created in Step 2 Failing to perform this step with SAN mode could yield a virtual machine that cannot be powered on 62
97. certain operations that use vCloud Director You should be familiar with vCloud Director and vCloud API concepts Every resource in vCloud Director can be accessed using either its unique ID or HREF the reference URL in the vCloud API The NET SDK provides wrapper utility classes for commonly used resources to make the programming easier The operations described in the following sections are m Getting Access to vCloud Director on page 92 Shows how to connect and authenticate with the vCloud API m Inventory Access on page 92 Shows how to retrieve data for different Organization types m Retrieving Catalog information on page 96 Shows how to retrieve Catalog entries for backup m Retrieving vApp Configuration on page 97 Shows how to list virtual machines and vApp configuration data m Preventing Updates toa vApp During Backup or Restore on page 98 Shows how to use maintenance mode to quiesce vApp configuration m Associating vCloud Resources with vSphere Entities on page 99 Shows how to get Managed Object References of virtual machines and storage resources from vCloud Director m Restoring vApps on page 101 Shows how to import virtual machines into vApps Getting Access to vCloud Director The backup restore software component must use system administrator privileges to connect to vCloud Director so that it can access any Organization The system administrator alw
98. chine so customers can use vSphere resource pools to minimize the performance impact of backup For example the backup proxy can be in a lower priority resource pool than the production ESX ESXi hosts VMware Inc 25 Virtual Disk Programming Guide 26 m If virtual machines and the backup proxy are on a private network customers can choose unencrypted data transfer NBD is faster and consumes fewer resources than NBDSSL However VMware recommends encryption for sensitive information even on a private network SSL Certificates and Security The VDDK 5 1 release has been security hardened and virtual machines can be set to verify SSL certificates On Windows the keys shown in Table 3 3 are required at the following Windows registry path m For 64 bit Windows systems use HKEY_LOCAL_MACHINE SOFTWARE Wow6432Node VMware Inc VMware Virtual Disk Development Kit To support registry redirection registry entries needed by VDDK on 64 bit Windows must be placed under registry path Wow6432Node This is the correct location for both 32 bit and 64 bit binaries on 64 bit Windows Table 3 3 Windows Registry Keys for VDDK Key Name Type Possible Settings InstallPath REG_SZ lt path to the install directory gt VerifySSLCertificates REG_DWORD Either 0 off 1 on Default is 0 zero If 0 SSL certificate validation will be ignored If 1 the SSL certificate of the target virtual machine must be m properly signed by a certificate authorit
99. chines must go through a stun unstun cycle triggered either by power on migrate resume after suspend or snapshot create delete revert before the virtual machine reconfiguration takes effect To enable changed block tracking with the vSphere Client 1 Select the virtual machine and ensure that Summary gt VM Version says 7 or higher compatibility 2 Inthe Summary tab click Edit Settings gt Options gt Advanced gt General 3 Inthe right side of the dialog box click Configuration Parameters 4 Inthe new dialog box locate or create a row with name ctkEnab1Led and set its value to true not false See above concerning the stun unstun cycle To enable changed block tracking and back up with the VMware vSphere API 1 Query change tracking status of the virtual machine If false activate changed block tracking configSpec changeTrackingEnabled new Boolean true 2 Create a snapshot of the virtual machine The snapshot operation causes a stun unstun cycle CreateSnapshot_Task VMmoRef SnapshotName Description memory_files quiesce_filesystem 3 Starting from the snapshot s ConfigInfo work your way to the BackingInfo of all virtual disks in the snapshot This gives you the change IDs for all the disks of the virtual machine 4 Hold onto the change IDs and do a full backup of the snapshot since this is the first time for backup VixDiskLib_Read snapshotDiskHandle startSector numSectors amp buffer C not Java 5 D
100. choose to overwrite an existing vApp For instance the restore software might need to overwrite a vApp with data corruption You can also choose to restore a vApp that no longer exists for instance a vApp that was accidentally deleted You can choose whether to keep the same vApp name and other vApp attributes or you can choose to change attributes during the restore process If the attributes of the restored vApp no longer conform to the environment because of changes since the backup was taken you can select new values for the non conforming attributes You might want to restore an existing vApp to an earlier state or you might want to replace it because it has become corrupted VMware Inc 89 Virtual Disk Programming Guide To restore an existing vApp 1 2 7 Identify the child virtual machines of the vApp using the metadata stored with the backup Connect to vCenter Server as a user with sufficient permissions to access the virtual machines and restore the virtual machines in the vSphere environment This step restores the virtual disk files and virtual machine configuration If you are overwriting an existing vApp you generally restore the files to the same data store that vCloud Director currently uses for the vApp Connect to vCloud Director and authenticate as an administrator which gives you backup and restore privileges Locate the corrupted vApp using the ID retrieved from the metadata in the backup store Select
101. configuration files in plain text or in the registry In order to be able to use SSPI the following conditions must be met m Connections must be made directly to a vSphere Server or a VirtualCenter Server version 2 5 or later Applications and their connections must employ one of two user account arrangements The connection must be established either m Using the same user context with the same user name and password credentials on both the proxy and the vSphere Server or m Using a domain user Attempts by applications to establish connections using the Local System account context will fail m User contexts must have administrator privileges on the proxy and have the VCB Backup User role assigned in vSphere or VirtualCenter If your setup meets all these conditions you can enable SSPI authentication by setting USERNAME to __sspi__ For SSPI the password must be set but it is ignored It can be set to null Always call VixDiskLib_Disconnect before the end of your program VMX Specification On VMware platform products vmx is a text file usually located in the same directory as virtual disk files specifying virtual machine configuration The Virtual Machine eXecutable VMX process is the user space component or world of a virtual machine The virtual disk library connects to virtual machine storage through the VMX process When specifying connection parameters see Data Structures in Virtual Disk API on p
102. d on a resource pool configured in vCenter Server named dao_w2k8_vc More information on this server can be obtained by using the vCloud API and its reference URL which is available as the href property The MoRef element provides the ID of the resource pool that backs the given VDC as known to vSphere Since a MoRef is treated as an opaque value the VimObjectType element specifies the type of object that the MoRef points to Combining these elements enables you to use the vSphere API and to locate the Resource Pool served by the specified vCenter Server VMware Inc Backing Up vApps in vCloud Director Example 8 15 XML Mapping a Datacenter URL to a MoRef lt AdminVdc gt lt VCloudExtension required false gt lt vmext VimObjectRef gt lt vmext VimServerRef type application vnd vmware admin vmwvirtualcenter xmL name dao_w2k8_vc href https 10 20 140 167 api admin extension vimServer e7026985 19fF6 4b9a 9dOd 588629e63347 gt lt vmext MoRef gt resgroup 52 lt vmext MoRef gt lt vmext Vim0bjectType gt RESOURCE_POOL lt vmext VimObjectType gt lt vmext VimObjectRef gt lt VCloudExtension gt lt AdminVdc gt Example 8 16 shows how to use SDK helper methods to access the vSphere specific information for the virtual machines of a given vApp The return value of the methods has type VimObj ectRefType which provides a reference to a vCenter Server a MoRef to the vSphere entity and the t
103. d to the PropertyCollector the minimum number of elements is one Two mechanisms can retrieve data from PropertyCollector m RetrieveProperties A one time request for all of the desired properties This can involve a lot of data and has no refresh option RetrievePropertiesEx has an additional options parameter m Update requests PropertyCollector update requests take two forms polling and waiting see below Requesting Updates The update method is the way to keep properties up to date In either Polling or Waiting it is first necessary to register your FilterSpec array object with the PropertyCollector You do this using the CreateFilter method which sends a copy of your FilterSpec to the server Unlike the RetrieveProperties method FilterSpec is retained after CreateFilter operation The following code shows how to set FilterSpec We already showed examples of creating pspec and ospec in the examples above The PropertyCollector wants an array of FilterSpec objects so PropertyFilterSpec fs new PropertyFilterSpec fs setPropSet pspec fs setObjectSet ospec PropertyFilterSpec fsa new PropertyFilterSpec fs ManagedObjectReference pcRef serviceContent getPropertyCoLllector This next statement sends the filter to the server for reference by the PropertyCollector ManagedObjectReference pFilter serviceConnection CreateFilter pcRef fsa Boolean FALSE If you wish to begin polling you ma
104. dcRef vDC where the new vApp will be created Vapp vapp vimServer ImportVmAsVApp importVmAsVAppParamsType Task is embedded in vapp foreach VM vm in vms Import remaining VMs from VIM Server into existing vApp importVmIntoVAppParamsType vmMoRefField moref vSphere ID from backup data importVmIntoVAppParamsType vAppField vapp vApp to hold restored VMs Task task vimServer ImportVmIntoVApp importVmIntoVAppParamsType J Example 8 18 shows the corresponding REST API calls used to rebuild a vApp in vCloud Director Example 8 18 REST API Calls To Restore a vApp POST https vCloud api admin extension vimServer id importVmAsVApp POST https vCloud api admin extension vimServer id importVmIntoExistingVApp Conclusion 102 This chapter provided an overview of how to use the vCloud SDK for NET to back up and restore vApps in vCloud Director This information serves as a guide to using the vCloud SDK for writing backup and restore software Other documentation is require to supplement aspects not described in this chapter The examples in this chapter are not intended to be complete They are intended only to illustrate the method calls you would use during backup and restore operations with vCloud Director and vCenter Server For more detail about the SDK methods and examples of their use see the vCloud SDK for NET Developer s Guide VMware Inc Virtual Disk Mount API As of the VDDK 1 1 rele
105. ding to the media server The attached HotAdd disk is shown in Figure 3 2 Figure 3 2 HotAdd Transport Mode for Virtual Disk ESX host ESX host virtual machine backup proxy virtual appliance VMware Tools application Virtual Disk API shared storage network virtual machine VMware Tools shared storage SCSI HotAdd Running the backup proxy as a virtual machine has two advantages it is easy to move a virtual machine to a new media server and it can back up local storage without using the LAN although this incurs more overhead on the physical ESX ESXi host than when using SAN transport mode VMware Inc Virtual Disk Interfaces About the HotAdd Proxy The HotAdd backup proxy must be a virtual machine HotAdd involves attaching a virtual disk to the backup proxy like attaching disk to a virtual machine In typical implementations a HotAdd proxy backs up either Windows or Linux virtual machines but not both For parallel backup sites can deploy multiple proxies The HotAdd proxy must have access to the same datastore as the target virtual machine and the VMFS version and data block sizes for the target VM must be the same as the datastore where the HotAdd proxy resides If the HotAdd proxy is a virtual machine that resides on a VMFS 3 volume choose a volume with block size appropriate for the maximum virtual disk size of virtual machines that customers want to back up as shown in Table 3 2 This caveat does not
106. disk See Close a Local or Remote Disk on page 30 VixDiskLib_Connect Connects to the virtual disk library to obtain services See also ConnectEx VixDiskLib_ConnectEx Connects to optimum transport See Connect to VMware vSphere on page 37 VixDiskLib_Create Creates a virtual disk according to specified parameters VixDiskLib_CreateChild Creates a child disk redo log or delta link for a hosted virtual disk VixDiskLib_Defragment Defragments the sectors of a virtual disk VixDiskLib_Disconnect Disconnects from the library See Disconnect from Server on page 35 VixDiskLib_EndAccess Notifies a host that it may again relocate a virtual machine See page 38 VixDiskLib_Exit Releases all resources held by the library See Clean Up and Exit on page 35 VixDiskLib_FreeErrorText Frees the message buffer allocated by GetErrorText VixDiskLib_FreeInfo Frees the memory allocated by GetInfo VixDiskLib_GetErrorText Returns the text description of a library error code VixDiskLib_GetInfo Retrieves information about a virtual disk VixDiskLib_GetMetadataKeys Retrieves all keys in the metadata of a virtual disk VixDiskLib_GetTransportMode Gets current transport mode See Get Selected Transport Method on page 38 VixDiskLib_Grow Increases size of an existing virtual disk VixDiskLib_Init Initializes the old virtual dis
107. e writeThrough false thinProvisioned lt unset gt eagerlyScrub lt unset gt uuid lt unset gt contentId lt unset gt changeld lt unset gt Designing vSphere Backup Solutions parent vim vm device VirtualDisk FlatVer2BackingInfo null connectable vim vm device VirtuaLDevice ConnectInfo dynamicType lt unset gt startConnected true allowGuestControl false connected true Fs controller for SCSI disk two controllerKey 44 unitNumber 1 size in MB SCSI disk two capacityInkB 131072 committedSpace lt unset gt shares vim SharesInfo null Ja cpuAllocation vim ResourceALlocationInfo dynamicType lt unset gt reservation 0 expandableReservation lt unset gt limit lt unset gt shares vim SharesInfo dynamicType lt unset gt shares 100 level normal overheadLimit lt unset gt memoryALLocation vim ResourceALlocationInfo dynamicType lt unset gt reservation 0 expandableReservation lt unset gt limit lt unset gt shares vim SharesInfo dynamicType lt unset gt shares 100 level normal overheadLimit lt unset gt cpuAffinity vim vm AffinityInfo null memoryAffinity vim vm AffinityInfo null networkShaper vim vm NetworkShaperInfo null swapPlacement lt unset gt VMware Inc 77 Virtual Disk Programming Guide 78 swapDirec
108. e Inc consolePreferences vim vm ConsolePreferences null powerOpInfo vim vm DefaultPowerOpInfo dynamicType lt unset gt powerOffType preset suspendType preset resetType preset defaultPowerOffType lt unset gt defaultSuspendType lt unset gt defaultResetType lt unset gt standbyAction powerOnSuspend Fs the number of CPUs numCPUs 1 the number of memory megabytes memoryMB 256 memoryHotAddEnabled lt unset gt cpuHotAddEnabled lt unset gt cpuHotRemoveEnabled lt unset gt deviceChange vim vm device VirtualDeviceSpec vim vm device VirtualDeviceSpec dynamicType lt unset gt operation add fileOperation lt unset gt CDROM device vim vm device VirtualCdrom dynamicType lt unset gt key number of CDROM key 42 deviceInfo vim Description null Designing vSphere Backup Solutions backing vim vm device VirtualCdrom RemotePassthroughBackingInfo dynamicType lt unset gt deviceName useAutoDetect lt unset gt exclusive false connectable vim vm device VirtualDevice ConnectInfo dynamicType lt unset gt startConnected false allowGuestControl true connected false Fy connects to this controller controllerKey 200 unitNumber 0 ty vim vm device VirtualDeviceSpec dynamicType lt unset gt operation add fileOperation lt unset gt SCSI controller device
109. e both designated by their moRef VMware Inc Designing vSphere Backup Solutions Managed Object References A managed object reference moRef is actually a handle and not the managed object itself While it is certain that a moRef always contains a unique value the unique value is only relative to the instance of vSphere to which you are connected For example if vCenter Server manages a cluster of ESXi hosts each ESXi host maintains its own managed object reference namespace and the vCenter must maintain a managed object reference namespace representing all of its servers So when an ESXi host is represented by a vCenter the vCenter must ensure that the managed object references are unique The vCenter accomplishes this by creating unique managed object reference names inside its own namespace which differ from the names that ESXi uses for the same managed objects A vSphere instance vCenter or ESXi tries to keep the moRef for a virtual machine consistent across sessions however consistency is not guaranteed For example unregistering and reregistering a virtual machine could result in a change to the moRef for the virtual machine Thus it is a bad idea to store a moRef and expect it to work correctly in future sessions or with a different vCenter Server Unique ID for a Different vCenter On one vCenter Server the moRef uniquely identifies a virtual machine If you need to track and inventory virtual machine backups across multipl
110. e in disaster recovery when vCenter Server runs on ESXi as a virtual machine A new vSphere 5 feature tries to prevent this if the ESXi host is managed by vCenter To circumvent this and restore the virtual machine you must first disassociate the host from vCenter In earlier releases vCenter management had less state but was revocable only from vCenter 1 Using the vSphere Client connect directly to the ESXi 5 0 or later host 2 Inthe Inventory left hand panel select the host In the right hand panel click Summary 3 Inthe box titled Host Management click Disassociate host from vCenter Server You do not need to put the host in Maintenance Mode 4 After the vCenter Server has been restored and is back in service use it to reacquire the host Currently there is no API to disassociate a host from vCenter Server Tips and Best Practices VDDK 5 0 contained two new VixDiskLib calls PrepareForAccess and EndAccess to disable and enable Storage vMotion during backup This prevents stale disk images from being left behind if a virtual machine has its storage moved while a backup is taking place VMware strongly recommends use of these calls When an ESX ESXi host is managed by vCenter Server vSphere API calls cannot contact the host directly they must go through vCenter If necessary especially during disaster recovery the administrator must disassociate the ESXi host from vCenter Server before the host can be contacted directly Advanced
111. e vCenter Servers you can use moRef together with instanceUuid You can see the instanceUuid at the following browser path https lt vcserver gt mob moid ServiceInstance amp doPath content about For direct connections to ESXi the host address and moRef uniquely identify a virtual machine However this moRef could be different from the one that vCenter Server returns hence the fallback to instanceUuid The instanceUuid was new in VMware vSphere 4 0 In previous releases the fallback was to Uuid Gathering Status and Configuration Information To save configuration of a virtual machine so you can restore it later you can use the PropertyCollector to get the virtual machine configuration The PropertyCollector is the most efficient mechanism to specify at the top level all of the managed objects that are of interest to your application It has methods for providing updates that indicate only changes to the previous state of these objects There are two mechanisms for acquiring these updates m Polling Check for changes The result is either no change or an object containing the changes One advantage of this mechanism is that it involves no network traffic except for a poll request and reporting Wait for updates Wait for updates is basically a blocking call to the PropertyCol lector This is only useful if you dedicate a program thread waiting for the call to unblock The advantage of this mechanism is that there is
112. e virtual disk is attached to a shared virtual SCSI bus ESX ESXi 3 5 supported only up to virtual hardware version 4 Changed block tracking can be enabled on virtual machines that have disks like these but when queried for their change ID these disks always return an empty string So if you have a virtual machine with a regular system disk and a pass through RDM as a data disk you can track changes only on the system disk Checking for Namespace You can avoid using the queryChangedDiskAreas API on ESX ESXi 3 5 based storage by parsing XML files for the namespace For prepackaged methods that do this see these SDK code samples Axis java com vmware samples version dispLaynewpropertieshost DispLayNewPropertiesHostV25 java Axis java com vmware samples version getvirtualdiskfiles GetVirtuaLDiskFilesV25 java DotNet cs DisplLayNewProperties DispLayNewPropertiesV25 cs DotNet cs GetVirtuaLDiskFiles GetVirtualDiskFilesV25 cs Low Level Restore Procedures The following sections describe how to recover virtual machines and restore virtual disk data m Restoring a Virtual Machine and Disk on page 73 m Restore of Incremental Backup Data on page 80 Restoring a Virtual Machine and Disk You cannot get write access to a virtual disk that is in active use For a full restore you first must ensure that the virtual disk is not in use by halting the parent virtual machine then performing the power off sequence The following code samp
113. ed for backup A side effect of this step is determining the arrangement and description of virtual machines on the host 2 Tell the host to take a snapshot of the target virtual machine using the vSphere API Use the quiesce flag but not the memory flag which is incompatible with quiesce The virtual machine continues to run while the snapshot provides a static quiesced view 3 Capture the virtual disk data and virtual machine configuration information vim vm ConfigInfo 4 On the ESXi host use the VDDK programming in C or C to open and read the virtual disk and snapshot files Copy them to backup media along with configuration information 5 Tell the host to delete the backup snapshot using the vSphere API VMware Inc 57 Virtual Disk Programming Guide 58 Communicating With the Server Ina typical vSphere deployment with many ESXi hosts an instance of vCenter Server manages the ESXi hosts and can move virtual machines from host to host vMotion to balance load and possibly save electricity by powering off an ESXi host VMware therefore recommends that backup applications communicate with the vCenter Server instead of with individual ESXi hosts The vCenter Server provides location transparency for vSphere Web Services developers The vCenter Server tracks virtual machines as they move through vMotion from one ESXi host to another and vCenter Server directs SDK operations to the ESXi host that currently runs a virt
114. ee the online reference guide Introduction to the VixDiskLib API m Windows C Program Files VMware VMware Virtual Disk Development Kit doc intro html m Linux usr share doc vmware vix disklib intro htm1 In a Web browser click the Error Codes link in the upper left frame and click any link in the lower left frame The right hand frame displays an alphabetized list of error codes with explanations Association With VIX API Errors The Virtual Disk API shares many errors with the VIX API which explains the VIX prefix The error codes for the VIX API are likely to be the same or almost the same as a comparable release of the VDDK For information about the VIX API including its online reference guide to functions and error codes see the developer support section of the VMware Web site https www vmware com support developer vix api index html Interpreting Errors Codes A VIX error is a 64 bit value A value of VIX_OK indicates success but otherwise if there is an error several bit regions in the 64 bit value might be set The least significant 16 bits are set to the error code described for VIX errors More significant bit fields might be set to other values As for the VIX API use the macro VIX_ERROR_CODE err to mask off bit fields not used by the VDDK Troubleshooting Dynamic Libraries On Windows the SSL library is placed in the same directory as other vixDiskLib dynamically loaded libraries On Linux functions th
115. een the time indicated by the change ID and the time of the snapshot If you specify change ID as star queryChangedDiskAreas returns a list of allocated disk sectors so your backup can skip the unallocated sectors of sparse virtual disk Suppose that you create an initial backup at time T1 Later at time T2 you take an incremental backup and another incremental backup at time T3 You could use differential backups instead of incremental backups which would trade off greater backup time and bandwidth for shorter restore time For the full backup at time T1 1 Keep a record of the virtual machine configuration VirtualMachineConfigInfo 2 Create a snapshot of the virtual machine naming it snapshot_T1 3 Obtain the change ID for each virtual disk in the snapshot changeId_T1 per VMDK 4 Back up the sectors returned by queryChangedDiskAreas avoiding unallocated disk 5 Delete snapshot_T1 keeping a record of changeId_T1 along with lots of backed up data For the incremental backup at time T2 1 Create a snapshot of the virtual machine naming it snapshot_T2 2 Obtain the change ID for each virtual disk in the snapshot changeId_T2 per VMDK 3 Back up the sectors returned by queryChangedDiskAreas snapshot_T2 changeId_T1 4 Delete snapshot_T2 keeping a record of changeId_T2 along with backed up data For the incremental backup at time T3 1 Create a snapshot of the virtual machine naming it snapshot_T3 At time
116. elete the snapshot when your backup has completed removeSnapshot_Task SnapshotName Boolean FALSE 6 Next time you back up this virtual machine create a snapshot and use QueryChangedDiskAreas with the change IDs from your previous backup to take advantage of changed block tracking changes theVM queryChangedDiskAreas SnapshotMoRef diskDeviceKey startPosition changeld Gathering Changed Block Information Associated with changed block tracking is changeId an identifier for versions of changed block data Whenever a virtual machine snapshot is created associated with that snapshot is a changeId that functions as a landmark to identify changes in virtual disk data So it follows that when a snapshot is created for the purpose of creating an initial virtual disk backup the changeId associated with that snapshot can be used to retrieve changes that have occurred since snapshot creation To obtain the changeId associated with any disk in a snapshot you examine the hardware array from the snapshot Any item in the devices table that is of type vim vm device VirtualDevice VirtualDisk encloses a class describing the backing storage obtained using getBacking that implements virtual disk If backing storage is one of the following disk types you can use the changeId property of the BackingInfo data object to obtain the changed VMware Inc 71 Virtual Disk Programming Guide 72 vim vm device VirtualDevice VirtuaLDiskFl
117. ents majorVersion and minorVersion represent the VDDK library s release number and dot release number The third fourth and fifth arguments specify log warning and panic handlers DLLs and shared objects are located in LibDir VixError vixError VixDiskLib_Init majorVer minorVer amp logFunc amp warnFunc amp panicFunc libDir You should call VixDiskLib_Init only once per process because of internationalization restrictions at the beginning of your program You should call VixDiskLib_Exit at the end of your program for cleanup For multithreaded programs you should write your own LogFunc because the default function is not thread safe In most cases you should replace VixDiskLib_Init with VixDiskLib_InitEx which allows you to specify a configuration file For information about InitEx see Initialize Virtual Disk API on page 35 Connect to a Workstation or Server VixDiskLib_Connect connects the library to either a local VMware host or a remote server For hosted disk on the local system provide null values for most connection parameters For managed disk on an ESX ESXi host specify virtual machine name ESX ESXi host name user name password and possibly port vixError VixDiskLib_Connect amp cnxParams amp srcConnection You can opt to use the VixDiskLibSSPICreds connection parameter to enable Security Support Provider Interface SSPI authentication SSPI provides the advantage of not storing passwords in
118. er of this section lists the available function calls in the vixMntapi library Under parameters in indicates input parameters and out indicates output parameters All functions that return vixError return VIX_OK on success otherwise a suitable VIX error code VixMntapi_Init Initializes the library Similar to VixDiskLib_InitEx see Initialize Virtual Disk API on page 35 VixError VixMntapi_Init uint32 majorVersion uint32 minorVersion VixDiskLibGenericLogFunc log VixDiskLibGenericLogFunc warn VixDiskLibGenericLogFunc panic const char libDir const char configFile Parameters m majorVersion in VixMntapi major version number currently must be 1 one m minorVersion in VixMntapi minor version number currently must be 0 zero m log in Callback function to write log messages m warn in Callback function to write warning messages m panic in Callback function to report fatal errors m libDir in and configFile in as for VixDiskLib_InitEx allowing you to tmpDirectory VixMntapi_Exit Cleans up the VixMntapi library void VixMntapi_ExitQ VMware Inc Virtual Disk Mount API VixMntapi_OpenDiskSet Opens the set of disks for mounting on a Windows virtual machine All the disks for a dynamic volume or Logical Disk Manager LDM must be opened together VixError VixMntapi_OpenDiskSet VixDiskLibHandle diskHandles int numberOfDisks uint32 openMode VixDiskSetHandle di
119. er to hostFolder TraversalSpec dc2hostFolder new TraversalSpec dc2hostFolder setType Datacenter dc2hostFolder setPath hostFolder We use the symbolic name folderTSpec which will be defined when we create the folderTSpec dc2vmFolder setSelectSet new SelectionSpec folderTSpec This TraversalSpec traverses ComputeResource to resourcePool TraversalSpec cr2resourcePool new TraversalSpec cr2resourcePool setType ComputeResource VMware Inc 65 Virtual Disk Programming Guide 66 cr2resourcePool setPath resourcePooL This TraversalSpec traverses ComputeResource to host TraversalSpec cr2host new TraversalSpec cr2host setType ComputeResource cr2host setPathC host This TraversalSpec traverses ResourcePool to resourcePool TraversalSpec rp2rp new TraversalSpec rp2rp setType ResourcePooL rp2rp setPath resourcePooL Finally we tie it all together with the Folder TraversalSpec TraversalSpec folderTS new TraversalSpec folderTS setName folderTSpec Used for symbolic reference folderTS setType Folder folderTS setPath childEntity folderTS setSelectSet new SelectionSpec folderTSpec dc2vmFolder dc2hostFolder cr2resourcePool rp2rp ObjectSpec ospec new ObjectSpec ospec setObj startingPoint This is where you supply the starting moRef usually root folder ospec setSkip Boolean FALSE ospe
120. ere 4 to an ESXi host 11 connections directly 23 connections through vCenter Server vSphere 5 to an ESXi host Limited by a transfer buffer for all NFC connections enforced by the host the sum of all NFC connection buffers to an ESXi host cannot exceed 32MB 52 connections through vCenter Server including the above per host limit VMware Inc Virtual Disk API Functions This chapter provides an overview of functions in the Virtual Disk API and includes the following sections m Virtual Disk Library Functions on page 27 m Start Up on page 28 m Disk Operations on page 30 m Error Handling on page 31 m Metadata Handling on page 31 m Cloning a Virtual Disk on page 31 m Disk Chaining and Redo Logs on page 32 m Administrative Disk Operations on page 34 m Shut Down on page 35 m Advanced Transport APIs on page 35 m Updating Applications for Advanced Transport on page 39 Multithreading Considerations on page 41 Capabilities of Library Calls on page 42 After a presentation of Virtual Disk API functions in alphabetic order sections focus on what the functions do in the normal order they would appear in a program except advanced transport functions SAN and HotAdd appear after the shutdown functions Virtual Disk Library Functions You can find the VixDiskLib API Reference by using a Web browser to open the doc index html1 file in the VDDK software d
121. ery VirtualMachine 3 Call Vim get_inventory_path to get the virtual disk name in its appropriate resource The VMDK filename is available as diskPath in the GuestDiskInfo data object 4 Using Perl s system cmd call run the extended vixDiskLibSamp1le exe program with virus option For ESX ESXi hosts you must specify host user and password options 5 Decontaminate any infected sectors that the virus scanner located Read and Write VMDK with vSphere WS API Version 2 5 and later of the VMware vSphere WS API contain some useful methods to manage VMDK files See the managed object type VirtualDiskManager which contains about a dozen methods similar to those in the Virtual Disk API documented here If you are interested navigate to VMware Infrastructure SDK on the Web and click VI API Reference Guide for the 2 5 version or VMware vSphere WS API Reference Guide for the 4 0 version Click All Types search for VirtualDiskManager and follow its link VMware Inc Designing vSphere Backup Solutions This chapter documents how to write backup and restore software for virtual machines running in vSphere and contains the following sections about the vSphere Storage APIs Data Protection VADP m Design and Implementation Overview on page 57 m Low Level Backup Procedures on page 64 m Low Level Restore Procedures on page 73 m Tips and Best Practices on page 81 m Windows Backup Implementations on p
122. es represent the virtual disk see Virtual Disk Types on page 19 the disk adapter see Adapter Types on page 23 VMware version and capacity of the disk sector typedef VixDiskLibDiskType diskType typedef VixDiskLibAdapterType adapterType typedef uint hwVersion typedef VixDiskLibSectorType capacity m VixDiskLibDiskInfo Types represent the geometry in the BIOS and physical disk the capacity of the disk sector the disk adapter see Adapter Types on page 23 the number of child disk links redo logs and a string to help locate the parent disk state before redo logs VixDiskLibGeometry biosGeo VixDiskLibGeometry physGeo VixDiskLibSectorType capacity VixDiskLibAdapterType adapterType int numLinks char parentFileNameHint m VixDiskLibGeometry Types specify virtual disk geometry not necessarily the same as physical disk typedef uint32 cylinders typedef uint32 heads typedef uint32 sectors Credentials and Privileges for VMDK Access Local operations are supported by local VMDK Access to ESX ESXi hosts is authenticated by login credentials so with proper credentials VixDiskLib can reach any VMDK on an ESX ESXi host VMware vSphere has its own set of privileges so with the proper privileges see below and login credentials VixDiskLib can reach any VMDK on an ESX ESXi host managed by vCenter Server VixDiskLib supports the following m Both read only and read write modes m Read only access to disk ass
123. essary to add an element for each type of object that you wish to query for properties The following is a code sample of a PropertySpec This code demonstrates how to specify a PropertySpec for several types of target objects PropertySpec folderSp new PropertySpec folderSp setType Folder folderSp setAL1l Boolean FALSE folderSp setPathSet new String parent name PropertySpec dcSp new PropertySpec dcSp setType Datacenter dcSp setA1l1 Boolean FALSE dcSp setPathSet new String parent name PropertySpec rpSp new PropertySpec rpSp setType ResourcePool rpSp setAL1L BooLlean FALSE rpSp setPathSet new String parent name vm PropertySpec crSp new PropertySpec crSp setType ComputeResource crSp setA1ll Boolean FALSE VMware Inc Designing vSphere Backup Solutions crSp set PathSet new String parent name PropertySpec vmSp new PropertySpec vmSp setType VirtualMachine vmSp setAL1l BooLean FALSE vmSp setPathSet new String parent name summary config snapshot config hardware device Tie it all together PropertySpec pspec new PropertySpec folderSp dcSp rpSp crSp vmSp Getting the Data from the PropertyCollector Now that we have defined ObjectSpec and PropertySpec the where and what we need to put them into a FilterSpec that combines the two An array of FilterSpec elements is passe
124. estores Also SAN transport does not support writing to redo logs snapshots or child disks only to base disks Before vSphere 5 5 when writing to SAN during restore disk size had to be a multiple of the underlying VMFS block size otherwise the write to the last fraction of a disk would fail For example if virtual disk had a 1MB block size and the datastore was 16 3MB large the last 0 3MB did not get written unless the restore software added 0 7MB of zeroes to complete the block This was fixed in the ESXi 5 5 release Programs that open a local virtual disk in SAN mode might be able to read if the disk is empty but writing will throw an error Even if programs call VixDiskLib_ConnextEx with NULL parameter to accept the default transport mode SAN is selected as the preferred mode if SAN storage is connected to the ESXi host VixDiskLib should but does not check SAN accessibility on open With local disk programs must explicitly request NBD or NBDSSL mode For a Windows Server 2008 proxy set SAN policy to onlineAll Set SAN disk to read only except for restore You can use the diskpart utility to clear the read only flag SAN policy varies by Windows Server 2008 edition For Enterprise and Datacenter editions the default Windows SAN policy is off Line which is unnecessary when vSphere mediates SAN storage Best Practices for HotAdd Transport Deploy the proxy on VMFS 5 volumes or on VMFS 3 volumes capable of large block size see
125. eted vApp the backup restore application must identify the vApp from user input to locate the vApp metadata and virtual machine files on the backup storage medium After the virtual machines have been restored using vSphere APIs the vApp can be recomposed using the vCloud API The backup software must first create a vApp from one of the virtual machines then import the remaining virtual machines into the same vApp Recovering a Single Virtual Machine The process of recovering a single virtual machine from the backup storage medium is a special case of recovering a deleted vApp In the case of a deleted vApp the backup software must re create the vApp in vCloud Director then import the remaining virtual machines For a single lost virtual machine the backup software must only import the one virtual machine into the existing vApp Backing Up vCloud Director The vCloud SDK for NET does not offer any special features for backing up or restoring the vCloud Director application and its data Users should follow standard industry advice for protecting Tomcat applications and Oracle or SQL Server databases VMware Inc 91 Virtual Disk Programming Guide vCloud API Operations The following sections describe commonly used vCloud API operations using vCloud SDK for NET The API descriptions in this chapter do not provide complete backup restore implementation details but focus instead on identifying a set of vCloud API methods that facilitate
126. eters The VMware VSS Implementation On Windows Server 2008 disk UUIDs must be enabled for VSS quiesced snapshots Disk UUIDs might not be enabled if a virtual machine was upgraded from virtual hardware version 4 VMware VSS does not support virtual machines with IDE disks nor does it support virtual machines with an insufficient number of free SCSI slots Before vSphere 5 1 reverting to a writable snapshot sometimes left orphaned virtual disks that the system never removed In the vSphere 5 1 release writable snapshots are correctly accounted for as sibling snapshots This permits cleaner management because the disk chain matches the snapshot hierarchy and it avoids orphaned disks Linux backup software takes a read only snapshot so is not affected On Windows VSS backup software may create two snapshots one made writable by calling CreateSnapshot_task with the quiesce flag set true To add support for granular application control specify m whether pre freeze and post thaw scripts get invoked m whether quiescing gets invoked m VSS snapshot context application file system quiescing and so forth m VSS backup context full differential incremental m writers components to be involved during quiescing m whether to fail quiescing or continue if one of the writers fails to quiesce m retry count A VSS quiesced snapshot reports as VSS_BT_COPY to VSS hence no log truncation The VSS manifest can be downloaded with HTTP By def
127. eve vApp Configuration 97 Virtual Machine Information 98 Preventing Updates to a vApp During Backup or Restore 98 Associating vCloud Resources with vSphere Entities 99 Restoring vApps 101 Conclusion 102 A Virtual Disk Mount API 103 The VixMntapi Library 103 Types and Structures 103 Operating System Information 103 Disk Volume Information 104 Function Calls 104 VMware Inc Contents Virtual Disk Programming Guide VixMntapi_Init 104 VixMntapi_Exit 104 VixMntapi_OpenDiskSet 105 VixMntapi_OpenDisks 105 VixMntapi_GetDiskSetInfo 105 VixMntapi_FreeDiskSetInfo 106 VixMntapi_CloseDiskSet 106 VixMntapi_GetVolumeHandles 106 VixMntapi_FreeVolumeHandles 106 VixMntapi_GetOsInfo 106 VixMntapi_FreeOsInfo 107 VixMntapi_MountVolume 107 VixMntapi_DismountVolume 107 VixMntapi_GetVolumelInfo 107 VixMntapi_FreeVolumelnfo 107 Programming with VixMntapi 108 File System Support 108 Read Only Mount on Linux 108 VMware Product Platforms 109 Sample VixMntapi Code 109 Restrictions on Virtual Disk Mount 109 B Errors Codes and Open Source 111 Finding Error Code Documentation 111 Association With VIX API Errors 111 Interpreting Errors Codes 111 Troubleshooting Dynamic Libraries 111 Open Source Components 112 Glossary 113 Index 115 8 VMware Inc About This Book The VMware Virtual Disk Programming Guide introduces the Virtual Disk Development Kit VDDK and the vSphere Storage APIs Data Protection VAD
128. f Using the vCloud SDK for NET allows you to access vCloud Director from a C development environment These examples show how to use NET methods The vCloud SDK for NET simplifies access to the vCloud API For more information about using the SDK see the vCloud SDK for NET Developer s Guide VMware Inc 93 Virtual Disk Programming Guide The vCloud API is REST based For more information about the vCloud API see the vCloud API Programming Guide Example 8 4 shows the REST API calls that accomplish the tasks shown in Example 8 1 Example 8 2 and Example 8 3 after logging in Example 8 4 REST API Calls To Get Provider VDC GET https vCloud api admin GET https vCloud api admin org id GET https vCloud api admin vdc id GET https vCloud api admin extension GET https vCloud api admin extension providervdc id In general if you do not need admin views or provider views you can use an Organization reference to get a VDC reference and you can use the VDC reference to get a list of vApps belonging to the VDC Example 8 5 shows how to list the hierarchy of Organizations VDCs and vApps known to vCloud Director This example assumes you have already logged in to vCloud Director Example 8 5 List vApps in a VDC for a Given Organization Dictionary lt string ReferenceType gt organizationsMap client GetOrgRefsByName if CorganizationsMap null foreach string organizationName in organizationsMap Key
129. figuration information reports this second redo log as part of the snapshot This redo log represented the quiesced state of all the applications in the guest This redo log must be opened for backup with VDDK 1 2 or later The older VDDK 1 1 software cannot open the second redo log for backup Application consistent quiescing of Windows 2008 virtual machines is only available when those virtual machines are created in vSphere 4 1 or later Virtual machines created in vSphere 4 0 can be updated to enable application consistent quiescing by modifying a virtual machine s enableUUID attribute For information about VSS see the Microsoft TechNet article How Volume Shadow Copy Service Works For information about Security Support Provider Interface SSPI see the MSDN Web site Enable Windows 2008 Virtual Machine Application Consistent Quiescing 1 Start the vSphere Client and log in to a vCenter Server 2 Select Virtual Machines and Templates and click the Virtual Machines tab ow Right click the Windows 2008 virtual machine for which you are enabling the disk UUID attribute and select Power gt Power Off Wait for the virtual machine to power off Right click the virtual machine and click Edit Settings Click the Options tab and select the General entry in the settings column Click Configuration Parameters The Configuration Parameters window appears Click Add Row In the Name column enter disk EnableUUID In the Value column en
130. filled in VixMntapi_GetDiskSetInfo Retrieves information about the disk set VixError VixMntapi_GetDiskSetInfo VixDiskSetHandle handle VixDiskSetInfo diskSetInfo Parameters m handle in Handle to an open disk set m diskSetInfo out Disk set information to be filled in VMware Inc 105 Virtual Disk Programming Guide 106 VixMntapi_FreeDiskSetInfo Frees memory allocated by VixMntapi_GetDiskSetInfo void VixMntapi_FreeDiskSetInfo VixDiskSetInfo diskSetInfo Parameter m diskSetInfo in OS info to be freed VixMntapi_CloseDiskSet Closes the disk set VixError VixMntapi_CLloseDiskSet VixDiskSetHandle diskSet Parameter m diskSet in Handle to an open disk set VixMntapi_GetVolumeHandles Retrieves handles to volumes in the disk set The third parameter VixVolumeHandle can be a volume handle or an array of volume handles If you pass an array this function returns the volume handle for the first volume only If you pass a pointer such as VixVolumeHand1le volumeHand les it returns all the volume handles VixError VixMntapi_GetVoLumeHandLles VixDiskSetHandle diskSet int numberOfVoLumes VixVoLumeHandle voLumeHandles Parameters m diskSet in Handle to an open disk set m numberOfVolumes out Number of volume handles m volumeHandles out Volume handles to be filled in VixMntapi_FreeVolumeHandles Frees memory allocated by VixMntapi_GetVolumeHandles void
131. ges made during the backup window In the above procedure the virtual disk library is used in the second step only The other steps use a portion of the vSphere API called VADP to snapshot and save configuration of virtual machines The virtual disk in a cluster is managed by vSphere Managed Disk and Hosted Disk Analogous to a hard disk drive virtual disk files represent the storage volumes of a virtual machine Each is named with vmdk suffix On a system running VMware Workstation file systems of each guest OS are kept in VMDK files hosted on the system s physical disk VMDK files can be accessed directly on the host With the virtual machine file system VMFS on ESX ESXi hosts VMDK files again represent storage volumes of virtual machines They are on VMFS which often resides on shared storage in a cluster The vCenter Server manages the cluster storage so it can migrate vMotion virtual machines from one ESX ESXi host to another without moving VMDK files VMFS storage is therefore called managed disk VMFS disk can reside on a storage area network SAN attached to ESX ESXi hosts by Fibre Channel iSCSI or SAS connectors It can also reside on network attached storage NAS or on directly attached disk Figure 1 1 depicts the arrangement of managed disk in this case VMDK on a SAN hosted VMFS file system and hosted disk VMDK files on physical disk Figure 1 1 Managed Disk and Hosted Disk cluster VMFS1 LUN1
132. hen opening a managed disk provide valid credentials for the vCenter Server that manages the ESXi host with the disk The second parameter is currently just for identity tracking purposes and is limited to 50 characters It could be the virtual machine name or the name of your application If you run VixDiskLib_PrepareForAccess directly on an ESXi host the system throws an error saying VDDK HostAgent is not a vCenter cannot disable svMotion Every VixDiskLib_PrepareForAccess call should have a matching VixDiskLib_EndAccess call The VixDiskLib_EndAccess function notifies the host that a virtual machine s disks have been closed so operations that rely on the virtual disks to be closed such as vMotion can now be allowed Call this function after closing all the virtual disks and after deleting the virtual machine snapshot Normally this function is called after previously calling VixDiskLib_PrepareForAccess but you can call it to clean up after a crash Internally this function re enables the vSphere API method RelocateVM_Task vixError VixDiskLib_EndAccess amp cnxParams vmName Here is a code snippet showing use of PrepareForAccess in a backup program that waits up to 10 minutes for Storage vMotion to finish Regular vMotion would finish much faster than that New sample code accounts for VMODL_TYPE_VIM_FAULT_METHOD_ALREADY_DISABLED_FAULT if CappGlobals vmxSpec NULL for Cint i 0 i lt 10 i
133. hown in Table 3 1 VMDK Virtual Disk Files on page 20 This one line change to DoCreate causes creation of 200MB split VMDK files 200MB being the capacity set on the previous line unless the cap command line argument specifies otherwise VMware Inc Practical Programming Tasks Creating Remote Disk As stated in Support for Managed Disk on page 42 VixDiskLib_Create does not support managed disk To create a managed disk on the remote ESX ESXi host first create a hosted disk on the local Workstation then convert the hosted disk into managed disk with VixDiskLib_Clone over the network To create remote managed disk using the sample program type the following commands vix disklib sample create cap 1000000 virtdisk vmdk vix disklib sample clone virtdisk vmdk host esx3i user root password secret vmfsdisk vmdk You could write a virtual machine provisioning application to perform the following steps 1 Create a hosted disk VMDK with 2GB capacity using VixDiskLib_Create 2 Write image of the guest OS and application software into the VMDK using VixDiskLib_Write 3 Clone the hosted disk VMDK onto the VMFS file system of the ESX ESXi host vixError VixDiskLib_Clone appGlobals connection appGlobals diskPath srcConnection appGlobals srcPath amp createParams CloneProgressFunc NULL TRUE In this call appGlobals connection and appGolbals diskPath represent the remote VMDK on the ESX ESXi ho
134. ib connection to access virtual disk data At the present time VixDiskLib is not implemented for the Java language so this code is C language VixDiskLibConnectParams connectParams VixDiskLibConnection srcConnection connectParams serverName strdupC TargetServer connectParams creds uid userName strdupC root connectParams creds uid password strdupC yourPasswd connectParams port 902 VixError vixError VixDiskLib_Init 1 0 amp logFunc amp warnFunc amp panicFunc libDir vixError VixDiskLib_Connect amp connectParams amp srcConnection This next section of code shows how to open and read a specific virtual disk VixDiskLibHandle diskHandle vixError VixDiskLib_Open srcConnection diskPath flags amp diskHand1e uint8 mybuffer some_multipLe_of_512 vixError VixDiskLib_Read diskHandle startSector numSectors amp mybuffer Also getting the disk metadata size_t requiredLength 1 char buf new char 1 This next operation fails but updates requiredLength with the proper buffer size vixError VixDiskLib_GetMetadataKeys diskHandle buf requiredLength amp requiredLength delete buf buf new char requiredLength Create a large enough buffer vixError VixDiskLib_GetMetadataKeys diskHandle buf requiredLength NULL And finally close the diskHandle vixError VixDiskLib_Close diskHandle And if you are completely done with the VixDiskLib VixDi
135. ib_CLone to make a copy of the data on virtual disk A callback function supplied as the sixth parameter displays the percent of cloning completed For local hosted disk the adapter type is SCSI unless specified as IDE on the command line size is 200MB unless set by cap option and type is monolithic sparse for Workstation 5 For an ESX ESXi host adapter type is taken from managed disk itself using the connection parameters established by VixDiskLib_Connect The final parameter TRUE means to overwrite if the destination VMDK exists The clone option is an excellent backup method Often the cloned virtual disk is smaller because it can be organized more efficiently Moreover a fully allocated flat file can be converted to a sparse representation SSL Certificate Thumbprint The sample program in the VDDK 5 1 release added the thumb option to allow an SSL Certificate thumbprint to be provided and used The thumbprint is used for authentication through vCenter Server 48 VMware Inc Practical Programming Tasks This chapter presents some practical programming challenges not covered in the sample program including m Scan VMDK for Virus Signatures on page 49 m Creating Virtual Disks on page 50 m VMDK File Versions on page 51 m Working with Virtual Disk Data on page 52 m Managing Child Disks on page 53 m RDM Disks and Virtual BIOS on page 54 m Interfacing With VMware vSphere on page
136. ication progressFunc and callback data can be defined rather than NULL Type these commands to create a sample VMDK file the first line is for Linux only export LD_LIBRARY_PATH usr Lib vmware vix diskLib 1Lib64 vix disklib sample create sample vmdk As a VMDK file monolithic sparse growable in a single file virtual disk is initially 65536 bytes 2 16 in size including overhead The first time you write to this type of virtual disk as with DoFil1 below the VMDK expands to 131075 bytes 2 17 where it remains until more space is needed You can verify file contents with the dump option DoRedo This procedure calls VixDiskLib_CreateChild to establish a redo log A child disk records disk sectors that changed since the parent disk or previous child Children can be chained as a set of redo logs The sample program does not demonstrate use of VixDiskLib_Attach which you can use to access a link in the disk chain VixDiskLib_CreateChild establishes a redo log with the child replacing the parent for read write access Given a pre existing disk chain VixDiskLib_Attach creates a related child or a cousin you might say that is linked into some generation of the disk chain For a diagram of the attach operation see Figure 4 2 Child Disks Created from Parent on page 33 Write by DoFill This procedure calls VixDiskLib_Write to fill a disk sector with ones byte value FF unless otherwise specified by va
137. igSpec 1 setDevice scsiCtr1 scsiCtrl setKey 44 scsiCtr1l setSharedBus VirtualSCSISharing noSharing VMware Inc Designing vSphere Backup Solutions Formulate SCSI disk one deviceConfigSpec 2 setFileOperation VirtualDeviceConfigSpecFileOperation create deviceConfigSpec 2 setOperation VirtualDeviceConfigSpecOperation add VirtualDisk disk new VirtualDiskQ VirtualDiskFlatVer2BackingInfo diskfileBacking new VirtualDiskFlatVer2BackingInfo diskfileBacking setDatastore datastoreRef diskfileBacking setFileName volumeName diskfileBacking setDiskMode persistent diskfileBacking setSplit new Boolean false diskfileBacking setwriteThrough new Boolean false disk setKey 1000000 disk setControllerKey new Integer 44 disk setUnitNumber new Integer 0 disk setBacking diskfileBacking disk setCapacityInKB 524288 deviceConfigSpec 2 setDevice disk Formulate SCSI disk two deviceConfigSpec 3 setFileOperation VirtualDeviceConfigSpecFileOperation create deviceConfigSpec 3 setOperation VirtualDeviceConfigSpecOperation add VirtuaLDisk disk2 new VirtualDiskQ VirtualDiskFlatVer2BackingInfo diskfileBacking2 new VirtualDiskFlatVer2BackingInfoQ diskfileBacking2 setDatastore datastoreRef diskfileBacking2 setFileName voLlumeName diskfileBacking2 setDiskMode persistent diskfileBacking2 setSplit new Boolean false diskfileBacking2 setWriteThrough new Boolean false
138. in sectors options adapter ide scsi bus adapter type for create option default scsi start n start sector for dump fill options default 0 count n number of sectors for dump fill options default 1 val byte byte value to fill with for write option default 255 cap megabytes capacity in MB for create option default 100 single open file as single disk link default open entire chain multithread n start n threads and copy the file to n new files host hostname hostname IP addresss ESX 3 x or VC 2 x user userid user name on host default root password password password on host port port port to use to connect to host default 902 vm vmPath path to vm inventory path to vm that owns the virtual disk libdir dir Directory containing vixDiskLibPlugin library initex configfile Use VixDiskLib_InitEx ssmoref moref Managed object reference of VM snapshot mode mode Mode string to pass into VixDiskLib_ConnectEx thumb string Provides a SSL thumbprint string for validation The thumb option is anew security related feature in the VDDK 5 1 release See SSL Certificate Thumbprint on page 48 44 VMware Inc Virtual Disk API Sample Code The sample program s single option which opens a single link instead of the entire disk chain is supported for local hosted disk but not for remote managed disk To connect to an ESXi host with the sample program you
139. ion create SCSI disk one device vim vm device VirtualDisk dynamicType lt unset gt key number for SCSI disk one key 1000000 deviceInfo vim Description null backing vim vm device VirtuaLDisk FlatVer2BackingInfo dynamicType lt unset gt fileName datastore lt unset gt diskMode persistent split false writeThrough false thinProvisioned lt unset gt eagerlyScrub lt unset gt uuid lt unset gt contentId lt unset gt changelId lt unset gt parent vim vm device VirtualDisk FlatVer2BackingInfo connectable vim vm device VirtuaLDevice ConnectInfo dynamicType lt unset gt startConnected true allowGuestControl false connected true controller for SCSI disk one controllerKey 44 unitNumber 0 size in MB SCSI disk one 76 capacityInkB 524288 committedSpace lt unset gt shares vim SharesInfo null null VMware Inc C vim vm device VirtualDeviceSpec dynamicType lt unset gt operation add fileOperation create SCSI disk two device vim vm device VirtualDisk dynamicType lt unset gt key number of SCSI disk two key 100 deviceInfo vim Description null backing vim vm device VirtuaLDisk FlatVer2BackingInfo dynamicType lt unset gt fileName datastore lt unset gt diskMode persistent split fals
140. ion and ZIP file for download on the VMware Web site VMware Inc 17 Virtual Disk Programming Guide 18 VMware Inc Virtual Disk Interfaces VMware offers many options for virtual disk layout encapsulated in library data structures described here VMDK File Location on page 19 Virtual Disk Types on page 19 Data Structures in Virtual Disk API on page 21 Virtual Disk Transport Methods on page 23 VMDK File Location On ESX ESXi hosts virtual machine disk VMDK files are usually located under one of the vmfs volumes perhaps on shared storage Storage volumes are visible from the vSphere Client in the inventory for hosts and clusters Typical names are datastore1 and datastorez2 To see a VMDK file click Summary gt Resources gt Datastore right click Browse Datastore and select a virtual machine On Workstation VMDK files are stored in the same directory with virtual machine configuration VMX files for example path to disk on Linux or C My Documents My Virtual Machines on Windows VMDK files store data representing a virtual machine s hard disk drive Almost the entire portion of a VMDK file is the virtual machine s data with a small portion allotted to overhead Virtual Disk Types The following disk types are defined in the virtual disk library VMware Inc VIXDISKLIB_DISK_MONOLITHIC_SPARSE Growable virtual disk contained in a single virtual disk file This is the default type
141. ion can fail For example a VirtualMachineConfigSpec that contains information about so called Default Devices usually fails The list of default devices includes vim vm device VirtualIDEController vim vm device VirtualPS2Controller vim vm device VirtualPCIController vim vm device VirtualSlOController vim vm device VirtualKeyboard vim vm device VirtualVMCIDevice vim vm device VirtualPointingDevice VMware Inc 79 Virtual Disk Programming Guide However other controllers and devices must be explicitly included in the VirtualMachineConfigSpec Some information about devices is unneeded and can cause problems if supplied Each controller device has its vim vm device VirtualController device field which is an array of devices that report to the controller The server rebuilds this list when a virtual machine is created using the negative device key numbers supplied as a guide The relationship between controller and device must be preserved using negative key numbers in the same relationship as in the hardware array of VirtualMachineConfigInfo The parent property for virtual disk backing information must be set to null In the sample code for creating a virtual machine find vim vm device VirtualDisk FlatVer2BackingInfo on page 76 and page 77 The null setting is required because the pre backup snapshot causes the parent property to be populated with a reference to the base disk One other configuration needs substitution Virtu
142. ips and Best Practices on page 81 Licensing of Advanced Transports The advanced transport license for VDDK includes all transport types Multithreading Considerations In multithreaded programs disk requests should be serialized by the client program Disk handles are not bound to a thread and may be used across threads You can open a disk in one thread and use its handle in another thread provided you serialize disk access Alternatively you can use a designated open close thread as shown in the workaround below Multiple Threads and VixDiskLib VDDK supports concurrent I O to multiple virtual disks with certain limitations VMware Inc VixDiskLib_InitEx or VixDiskLib_Init should be called once per process from the main thread In the VixDiskLib_InitEx or VixDiskLib_Init function call do not specify logging callbacks as NULL This causes VixDiskLib to provide its default logging functions which are not thread safe If you are using VDDK in a multithreaded environment you must provide your own thread safe log functions When you call VixDiskLib_Open and VixDiskLib_Close VDDK initializes and uninitializes a number of libraries some of which do not work if called from multiple threads For example this fails Thread 1 VixDiskLib_Open VixDiskLib_Close TARO 623 seeped cetera tigi ee a E EE VixDiskLib_Open VixDiskLib_Close The workaround is to use one designated thread to do all opens and close
143. isk VMware recommends creating a file such as tmp lt uniqueName gt using mkstemp to formulate a unique name for the child 3 Call VixDiskLib_Close to close the base disk which is no longer needed 4 Now use VixMntapi_OpenDisks as you normally would with diskSet 0 tmp lt uniqueName gt and openF lags 0 meaning read write This allows writing to the child snapshot for journal reply and so forth without affecting the base disk Software developers should inform customers that the mounted disk set seems writable although the effect of changing files and altering directories is only temporary The base disk is read only To unmount read only disks 1 Call VixMntapi_CloseDiskSetQ to close the disk set 2 Call VixDiskLib_Unlink to remove the child snapshot tmp lt uniqueName gt VMware Inc Virtual Disk Mount API VMware Product Platforms Applications written using this release of VixMntapi can manipulate virtual disks created with ESX and ESXi VMware Server VMware Fusion VMware Player VMware Workstation and GSX Server Sample VixMntapi Code You call the VixMntapi functions after initializing VixDiskLib connecting to a virtual machine and opening a disk handle Example A 1 shows test code for Windows with the correct order of function calls Example A 1 Test source code for VixMntapi functions MountTest Q vixError VIX_ERR_CODE VixDiskLib_Init vixError VIX_ERR_CODE VixMntapi_Init
144. iskPath Shut Down All Virtual Disk API applications should call these functions at end of program Disconnect from Server VixDiskLib_Disconnect breaks an existing connection VixDiskLib_Disconnect srcConnection Clean Up and Exit VixDiskLib_Exit Q cleans up the library before exit VixDiskLib_ExitQ Advanced Transport APIs For managed disk the first release of VDDK required network access ESX ESXi host LAN or NBD transport With VDDK 1 1 programs can access virtual disks directly on a storage device LAN free Direct SAN access increases I O performance To select the most efficient transport method a set of APIs is available including m VixDiskLib_InitEx Initializes the advanced transport library You must specify the library location Replaces VixDiskLib_Init in your application m VixDiskLib_ListTransportModes Lists transport modes that the virtual disk library supports m VixDiskLib_ConnectEx Establishes a connection using the best transport mode available or one you select to access a given machine s virtual disk Currently it does not check validity of transport type Replaces VixDiskLib_Connect in your application Initialize Virtual Disk API Replacing VixDiskLib_Init VixDiskLib_InitEx initializes new releases of the library Parameters are similar except you should specify an actual libDir and the new configFile parameter For multithreaded programming you should write your own
145. istribution As in most reference manuals functions are organized alphabetically whereas in this chapter functions are ordered by how they might be called When the API reference says that a function supports only hosted disks it means virtual disk images hosted by VMware Workstation or similar products Virtual disk stored on VMFS partitions managed by ESX ESXi or vCenter Server is called managed disk The functions described in this chapter are based on concepts and employ data structures documented in Chapter 3 Virtual Disk Interfaces on page 19 If the library accesses virtual disk on VMFS I O by default goes through the ESX ESXi host which manages physical disk storage To use function calls that provide direct access to SAN storage start your program by calling the VixDiskLib_ConnectEx function as described in Advanced Transport APIs on page 35 VMware Inc 27 Virtual Disk Programming Guide Alphabetic Table of Functions Start 28 Function calls in the Virtual Disk API are listed alphabetically in Table 4 1 Table 4 1 Virtual Disk API Functions Function VixDiskLib_Attach Description Attaches the child disk chain to the parent disk chain VixDiskLib_Cleanup Removes leftover transports See Clean Up After Disconnect on page 39 VixDiskLib_Clone Copies virtual disk to some destination converting formats as appropriate VixDiskLib_Close Closes an open virtual
146. ities of Library Calls 42 Support for Managed Disk 42 Support for Hosted Disk 42 5 Virtual Disk API Sample Code 43 Compiling the Sample Program 43 Visual C on Windows 43 SLN and VCPROJ Files 43 C on Linux Systems 44 Makefile 44 Library Files Required 44 Usage Message 44 Walk Through of Sample Program 45 Include Files 45 Definitions and Structures 45 Dynamic Loading 46 Wrapper Classes 46 Command Functions 46 DoInfo 46 DoCreate 47 DoRedo 47 Write by DoFill 47 DoReadMetadata 47 DoWriteMetadata 47 DoDumpMetadata 47 DoDump 48 DoTestMultiThread 48 DoClone 48 SSL Certificate Thumbprint 48 6 Practical Programming Tasks 49 Scan VMDK for Virus Signatures 49 Creating Virtual Disks 50 Creating Local Disk 50 Creating Remote Disk 51 Special Consideration for ESX ESXi Hosts 51 VMDK File Versions 51 Working with Virtual Disk Data 52 Reading and Writing Local Disk 52 Reading and Writing Remote Disk 52 Deleting a Disk Unlink 52 Effects of Deleting a Virtual Disk 52 Renaming a Disk 52 Effects of Renaming a Virtual Disk 53 Working with Disk Metadata 53 Managing Child Disks 53 Creating Redo Logs 53 Virtual Disk in Snapshots 53 Windows 2000 Read Only File System 53 VMware Inc Contents Virtual Disk Programming Guide RDM Disks and Virtual BIOS 54 Restoring RDM Disks 54 Restoring the Virtual BIOS or UEFI 54 Interfacing With VMware vSphere 55 The VIX API 55 Virus Scan all Hosted Disk 55 The vSphere
147. ixError VixMntapi_MountVoLume VixVoLumeHandle volumeHandle Bool isReadOnly Parameters m volumeHand1e in Handle to a volume m isReadOn1y in Whether to mount the volume in read only mode Does not override openMode VixMntapi_DismountVolume Unmounts the volume VixError VixMntapi_DismountVolume VixVoLumeHandle volumeHandle Bool force Parameters m volumeHand1e in Handle to a volume m force in Force unmount even if files are open on the volume VixMntapi_GetVolumelnfo Retrieves information about a disk volume Some information such as the number of mount points requires you to set the open read only flag Some information is available only if a volume was previously mounted by VixMntapi_MountVolume The Windows registry returns volume information only for mounted disks On Windows the VixMntapi_GetVolumeInfo call returns a symbolic link from the VixVolumeInfo structure in the form vstor2 mntapi10 shared lt longhexnum gt You can transform this symbolic link into a target path by replacing with Device and deleting the final backslash then map a drive letter with DefineDosDevice DDD_RAW_TARGET_PATH and proceed as if you have a local drive Alternatively on Windows you can open a volume with CreateFile and traverse the file system with FindFirstFile VixError VixMntapi_GetVoLumeInfo VixVoLumeHandle volumeHandle VixVoLumeInfo info Parameters m volumeHand1e in Handle
148. k 20 83 licensing for advanced transports 41 limitations of vixMntapi library 109 linked clone backup 34 Linux installation 16 localization l10n 21 M managed disk 13 19 28 42 48 51 113 managed object reference moRef 59 Microsoft Shadow Copy 84 monolithic VMDK 19 20 32 47 48 50 113 MONOLITHIC_FLAT 19 20 MONOLITHIC_SPARSE 19 20 moref and unique ID 59 mounting virtual disk for backup 63 N nonpersistent disk mode 20 NVRAM backup and restore 54 O ObjectSpec and PropertySpec 59 open read only disk 108 open source components in VDDK 112 P packaging of Virtual Disk API 16 persistent disk mode 20 platforms supported for development 15 privileges needed in vCenter Server 22 products from VMware that are supported 15 property collector use of 64 PropertySpec and ObjectSpec 59 Q queryChangedDiskAreas 40 R RDM raw device mapping 31 54 60 72 73 80 115 Virtual Disk Programming Guide 116 read only disk mount 108 re creating a virtual machine from backup 63 redo logs and snapshots 20 22 32 53 restore process overview of 61 restoring a virtual machine to previous state 62 restrictions on vixMntapi library 109 role and privileges in vCenter Server 22 S sample program walk through 45 SAN and the Virtual Disk API 13 27 SCSI controller and Hot Add 84 session object for server communication 58 snapshot backing up a virtual disk 69 creating 69 deleting 70 restoring virtual disk 7
149. k Library The library provides access to virtual disks enabling a range of use cases for application vendors including m Back up a particular volume or all volumes associated with a virtual machine m Connect a backup proxy to vSphere and back up all virtual machines on a storage cluster m Read virtual disk and run off line anti virus scanning or package analysis of virtual machines m Write to virtual disk to perform off line centralized patching of virtual machines Manipulate virtual disks to defragment expand convert rename or shrink the file system image m Perform data recovery or virus cleaning on corrupt or infected off line virtual machines Developing for VMware Platform Products Ina VMware based data center commercial backup software is likely to access virtual disks remotely perhaps from a backup proxy The proxy can be a virtual machine or a physical machine with backup restore software installed and access to alternate storage such as a tape autochanger or equivalent 12 VMware Inc Introduction to the Virtual Disk API At a given point in time during the backup window backup software 1 Snapshots virtual machines in a cluster one by one or in parallel Virtual machines run off the snapshot 2 Copies the quiesced base disk or for incremental backup only changed blocks to backup media 3 Records the configuration of virtual machines 4 Reverts and deletes snapshots so virtual machines retain any chan
150. k contains function definitions for dynamic loading It also contains the LoadOneFunc procedure to obtain any requested function from the dynamic library and the DynLoadDiskLib procedure to bind it This demonstration feature could also be called runtime loading to distinguish it from dynamic linking To try the program with runtime loading enabled on Linux add DDYNAMIC_LOADING after g in the Makefile and recompile On Windows define DYNAMIC_LOADING in the project Wrapper Classes Below the dynamic loading block are two wrapper classes one for error codes and descriptive text and the other for the connection handle to disk The error wrapper appears in catch and throw statements to simplify error handling across functions Wrapper class VixDisk is a clean way to open and close connections to disk The only time that library functions VixDiskLib_Open and VixDiskLib_Close appear elsewhere aside from dynamic loading is in the CopyThread function near the end of the sample program Command Functions The print usage message appears next with output partially shown in Usage Message on page 44 Next comes the main function which sets defaults and parses command line arguments to determine the operation and possibly set options to change defaults Dynamic loading occurs if defined Notice the all zero initialization of the VixDiskLibConnectParams declared structure VixDiskLibConnectParams cnxParams 0 For
151. k library Replaced by InitEx function VixDiskLib_InitEx Initializes new virtual disk library See Initialize Virtual Disk API on page 35 VixDiskLib_ListTransportModes Available transport modes See List Available Transport Methods on page 37 VixDiskLib_Open Opens a virtual disk See Open a Local or Remote Disk on page 30 VixDiskLib_PrepareForAccess Notifies a host to refrain from relocating a virtual machine See page 38 VixDiskLib_Read Reads from an open virtual disk See Read Sectors From a Disk on page 30 VixDiskLib_ReadMetadata Retrieves the value of a given key from disk metadata VixDiskLib_Rename Changes the name of a virtual disk VixDiskLib_Shrink Reclaims blocks of zeroes from the virtual disk VixDiskLib_SpaceNeededForClone Computes the space required to clone a virtual disk in bytes VixDiskLib_Unlink Deletes the specified virtual disk VixDiskLib_Write Writes to an open virtual disk See Write Sectors To a Disk on page 30 VixDiskLib_WriteMetadata Updates virtual disk metadata with the given key value pair Up The VixDiskLib_Init and VixDiskLib_Connect functions must appear in all virtual disk programs VixDiskLib_Init has been superseded by VixDiskLib_InitExQ VMware Inc Virtual Disk API Functions Initialize the Library VixDiskLib_Init initializes the old virtual disk library The argum
152. l on the command line The default is to fill only the first sector but this can be changed with options start and count on the command line DoReadMetadata This procedure calls VixDiskLib_ReadMetadata to serve the rmeta command line option For example type this command to obtain the universally unique identifier vix disklib sample rmeta uuid sampLe vmdk DoWriteMetadata This procedure calls VixDiskLib_WriteMetadata to serve the wmeta command line option For example you can change the tools version from 1 to 2 as follows vix disklib sampLe wmeta toolsVersion 2 sample vmdk DoDumpMetadata This procedure calls VixDiskLib_GetMetadataKeys then VixDiskLib_ReadMetadata to serve the meta command line option Two read metadata calls are needed for each key one to determine length of the value string and another to fill in the value See Get Metadata Table from Disk on page 31 In the following example the sample program connects to an ESX ESXi host named esx3 and displays the metadata of the Red Hat Enterprise Linux client s virtual disk For an ESX ESXi host path to disk might be storage1 followed by the virtual machine name and the VMDK filename VMware Inc 47 Virtual Disk Programming Guide vix diskLib sample meta host esx3 user admin password secret storage1 RHEL5 RHELS vmdk geometry sectors 63 geometry heads 255 geometry cylinders 522 adapterType buslogic toolsVersio
153. le demonstrates how to power off a Virtual Machine At this point we assume that you have a ManagedObjectReference to the VM vmMoRef Power on would need a ManagedObjectReference to the host running the VM hostMoRef ManagedObjectReference taskRef serviceConnection powerOffVm vmMoRef With SAN transport mode you must create a snapshot of the virtual machine before virtual disk restore See Creating a Snapshot on page 69 If at restore time the virtual machine had a pre existing snapshot you must delete it otherwise SAN mode restore will fail For other transport modes the restore snapshot is optional but recommended for consistency with SAN transport In this phase you use VixDiskLib to reload contents of the Virtual Disk so the following code is C not Java At this point we assume that you already have a VixDiskLib connection to the server machine uint8 mybuffer some_multipLe_of_512 int mylocalfile open localfile openflags Contains backup copy of virtual disk read mylocalfile mybuffer sizeof mybuffer vixError VixDiskLib_Open srcConnection path flags amp diskHandle VixDiskLib_Write diskHandle startsector sizeof mybuffer 512 mybuffer With SAN transport mode you must revert to and delete the snapshot If you forget the snapshot revert snapshot delete will fail due to CID mismatch so the virtual machine cannot be powered on If you forget the snapshot delete the extraneous
154. le for a version 3 virtual disk you can see a pointer to its ctk vmdk ancillary file For example version 3 Change Tracking File changeTrackPath Windows 2008R2x64 2 ctk vmdk The changeTrackPath setting references a file that describes changed areas on the virtual disk If you want to back up the changed area information then your software should copy the ctk vmdk file and preserve the Change Tracking File line in the vmdk descriptor file If you do not want to back up the changed area information then you can discard the ancillary file remove the Change Tracking File line read the VMDK file data as if it were version 1 and roll back the version number on restore VMware Inc 51 Virtual Disk Programming Guide Working with Virtual Disk Data The virtual disk library reads and writes sectors of data It has no interface for character or byte oriented I O Reading and Writing Local Disk Demonstrating random I O this function reads a sector at a time backwards through a VMDK If it sees the string VmWare it substitutes the string VMware in its place and writes the sector back to VMDK incLude lt string gt static void DoEdit void VixDisk disk appGlobals connection appGlobals diskPath appGlobals openFlags uint8 buf VIXDISKLIB_SECTOR_SIZE VixDiskLibSectorType i string str for i appGlobals numSectors i gt 0 i VixError vixError vixError VixDiskLib_Read disk
155. logFunc because the default logging function is not thread safe On Windows LibDir could be C Program Files VMware VMware Virtual Disk Development Kit On Linux LibDir is probably usr 1ib vmware vix disk1ib VixError vixErr VixDiskLib_InitEx majorVersion minorVersion amp logFunc amp warnFunc amp panicFunc 1ibDir configFile Logged messages appear by default in a temporary folder or log directory for VDDK and for many other VMware products See Location of Log Files on page 37 VMware Inc 35 Virtual Disk Programming Guide 36 The currently supported entries in the configFi le are listed below The correct way to specify a configuration is name va Lue See Example 4 1 for a sample configuration file tmpDirectory lt TempDirectoryForLogging gt vixDiskLib transport LogLevel Overrides the default logging for vixDiskLib transport functions not including NFC The default value is 3 The range is 0 to 6 where 6 is most verbose and 0 is quiet vixDiskLib disklib EnableCache Caching by vixDiskLib is off 0 by default Setting 1 turns it on Caching increases performance when information is read repeatedly or accessed randomly In backup applications information is usually accessed sequentially and caching can actually reduce performance Moreover with caching backup applications risk getting stale information if a disk sector is rewritten by another application before the cache is refreshed vix
156. machines When you work with a single vApp in vCloud Director you might be working with a number of virtual machines in vSphere To back up a vApp or set of vApps 1 Connect to vCloud Director and access the organization where vApp or vApps will be backed up 2 When backing up a vApp for a given Organization or VDC in vCloud Director access the vCloud Director inventory for a list of all desired vApps 3 Select maintenance mode for each vApp to prevent updates during the backup process 4 Collect all the metadata related to the vApp s including any user defined metadata associated with any given vApp 5 Use the vApp metadata to identify the virtual machines associated with each vApp 6 Connect to vCenter Server as a user with sufficient permissions to access the virtual machines Use the vSphere inventory to locate the virtual machine configuration and virtual disk files 7 Use the VMware APIs for Data Protection to back up the vSphere virtual machine files a optional Save a snapshot of the virtual machine b Save the virtual machine configuration using the WS API c Save the virtual disks using the VDDK API d optional Delete the virtual machine snapshot if applicable 8 Store the vApp metadata in an appropriate format along with the associated virtual machine files 9 Deselect maintenance mode for each vApp The Restore Process The restore process offers some options to the administrator When you restore a vApp you can
157. machines are known individually to vSphere To complete the restore operation the backup software needs to re create the restored vApp so that all the member virtual machines are created as child virtual machines of the vApp To re create the vApp using the vCloud SDK for NET the backup software must use two method calls ImportVmAsVapp and ImportVmIntoVapp Use the ImportVmAsVapp method to create a vApp from any one of the child virtual machines Then call the ImportVmIntoVapp method once for each remaining child virtual machine Example 8 17 shows how to use both methods to create a vApp using the vCloud SDK Example 8 17 Importing Virtual Machines into vApps lt Summary gt Reference to hold the vCloud Client reference lt summary gt private static VcloudAdminExtension extension null vcloudClient login user password extension vcloudClient getVcloudAdminExtension Get references for known VIM Servers Dictionary lt string ReferenceType gt vimServerRefsByName extension GetVMWVimServerRefsByName Select VIM Server Reference VMWVimServer vimServer VMWVimServer GetVMWVimServerByReference vcloudClient vimServerRefsByName vimServerName Import first VM from VIM server as vApp ImportVmIntoVAppParamsType importVmIntoVAppParamsType new ImportVmIntoVAppParamsType importVmIntoVAppParamsType vmMoRefField moref vSphere ID from backup data importVmIntoVAppParamsType vdcField v
158. mand a user name and password unless the session was recently authenticated 84 VMware Inc Designing vSphere Backup Solutions When performing VSS quiescing while creating the snapshot of a Windows virtual machine VMware Tools generate a vss manifest zip file containing the backup components document BCD and writer manifests The host agent stores this manifest file in the snapshotDir of the virtual machine Backup applications should get the vss manifest zip file so they can save it to backup media There are several ways to get this file m Using the datastore access HTTPS protocol for example by browsing to https lt server or host gt folder and continuing downward to the snapshot directory until you find the vss manifest zip file m By calling the CopyDatastoreFile_Task method in the vSphere API This method accepts the URL formulated above for HTTPS or a datastore path CopyVirtualDisk_Task is for VMDK files m With the vifs command in the vMA or vCLI m With the Copy DatastoreItem cmdlet in the PowerCLI requires PowerShell and VMware snap in Windows 2008 application level quiescing is performed using a hardware snapshot provider After quiescing the virtual machine the hardware snapshot provider creates two redo logs per disk one for the live virtual machine writes and another for the VSS and writers in the guest to modify the disks after the snapshot operation as part of the quiescing operations The snapshot con
159. mbered VMDK file stores changes made to the virtual disk lt diskname gt since the original parent disk or previously numbered redo log in other words the previous snapshot lt diskname gt lt gt vmdk SE_SPARSE Space efficient sparse SeSparse format In vSphere 5 1 and later used by VMware View to optimize linked clone templates n a Snapshot of a virtual machine which includes pointers to all its vmdk virtual disk files lt vnname gt Snapshot vmsn For lazy zeroed thick disk all blocks are allocated and data written to used blocks however unused blocks are left as is so they may contain data from previous use Many storage systems will zero out unused blocks in the background With eager zeroed thick disk unused blocks are zeroed out at allocation time VMware Inc Virtual Disk Interfaces Thin Provisioned Disk With thin provisioned disk the vSphere Client may report that provisioned size is greater than disk capacity Provisioned size for a thin disk is the maximum size the disk will occupy when fully allocated Actual size is the current size of the thin disk Overcommit means that if all thin disks were fully provisioned there would not be enough space to accommodate all of the thin disks Internationalization and Localization The path name to a virtual machine and its VMDK can be expressed with any character set supported by the host file system As of vSphere 4 and Workstation 7 VMware
160. mentations The disk implementation type is important because m Onrestore you should re create virtual disk with the same disk type as the original virtual machine used m A disk backed by a pass through raw device mapping RDM mostly bypasses the ESXi storage stack You cannot make a snapshot of this virtual disk type Therefore you cannot back up pass through RDM disk using the snapshot method described in this document For more information about the Java APIs read the first several chapters of the VMware vSphere Web Services SDK Programming Guide and related pages of the Web based VMware vSphere API Reference Documentation Both are available at http www vmware com support developer vc sdk Examples in this chapter assume that you have set up the vSphere SDK as described in documentation Doing a Backup Operation After your program obtains information about what is available to back up it can perform a backup The three steps to the backup process are m Create a Temporary Snapshot on the Target Virtual Machine on page 60 m Extract Backup Data from the Target Virtual Machine on page 61 and save configuration information m Delete the Temporary Snapshot on page 61 Prerequisites for Backup To complete a backup the calling program requires the permissions shown in Table 7 1 Table 7 1 Required Permissions to Complete a Backup Privilege Category Privilege Subcategory Privilege Virtual Machine Provisioning Allo
161. metadata from the backup store Deselect maintenance mode for the vApp NOTE This is a simplified view of the restore process The exact process you use will depend on the features provided by your software For instance if the datastore is full the software could offer to migrate the vApp to a different datastore Use Cases Overview 90 The following sections give an overview of use cases related to the backup and restore processes Managing Credentials Backup software needs vCloud Director access to manage vApps at the metadata level and vCenter Server access to manage vApps at the virtual machine and virtual disk level The backup software must collect and retain authentication credentials for both vCloud Director and vCenter Server For information about vCloud Director authentication see Getting Access to vCloud Director on page 92 For information about vSphere authentication see the vSphere Web Services SDK Programming Guide VMware Inc Backing Up vApps in vCloud Director Finding a vApp There are different ways to locate a vApp managed by vCloud Director One way is to traverse the vCloud Director inventory Another way is to use the query service Inventory Traversal Using the vCloud Director inventory to locate a vApp requires navigating a hierarchy of containers based on organizational and resource divisions The process is explained in Inventory Access on page 92 Using the Query Service The v
162. n 1 virtualHWersion 7 Tools version and virtual hardware version appear in the metadata but not in the disk information retrieved by Dolnfo on page 46 Geometry information and adapter type are repeated but in a different format Other metadata items not listed above might exist DoDump This procedure calls VixDiskLib_Read to retrieve sectors and displays sector contents on the output in hexadecimal The default is to dump only the first sector numbered zero but you can change this with the start and count options Here is a sequence of commands to demonstrate vix disklib sample create sample vmdk vix disklib sample fill val 1 sample vmdk vix disklib sample fill val 2 start 1 count 1 sample vmdk vix diskLib sample dump start count 2 sample vmdk od c sample vmdk On Linux or Cygwin you can run the od command to show overhead and metadata at the beginning of file and the repeated ones and twos in the first two sectors The dump option of the sample program shows only data not overhead DoTestMultiThread This procedure employs the Windows thread library to make multiple copies of a virtual disk file Specify the number of copies with the multithread command line option For each copy the sample program calls the CopyThread procedure which in turn calls a sequence of six Virtual Disk API routines On Linux the multithread option is unimplemented DoClone This procedure calls VixDiskL
163. n m SAN and HotAdd advanced transports m VixDiskLib_PrepareForAccess and VixDiskLib_EndAccess to delay Storage VMotion VMware Inc Virtual Disk API Sample Code This chapter discusses the VDDK sample program in the following sections m Compiling the Sample Program on page 43 m Usage Message on page 44 m Walk Through of Sample Program on page 45 Compiling the Sample Program The sample program is written in C although the Virtual Disk API also supports C For compilation to succeed the correct DLLs or shared objects must be loaded You can ensure the success of dynamic loading in a variety of ways m Set the path inside the VDDK program m Set the path for the shell being used in Linux or in Visual Studio for Windows For a default installation the Linux path is usr share doc vmware vix disklib samp Le m In Windows set the Path element in the System Variables To do this in Windows XP right click Computer gt Properties gt Advanced gt Environment Variables select Path in the System Variables lower list click Edit and add the path of the VDDK bin directory In Windows 7 right click Computer gt Properties gt Advanced System Settings gt Environment Variables select Path in the System Variables list click Edit and add the path of the VDDK bin directory C Program Files VMware VMware Virtual Disk Development Kit doc samp1e is the default path Note that VDDK loads DLLs by rela
164. n extract information about a guest operating system from its virtual disks so your backup application can determine the type of operating system that is involved This allows mounting the volumes to device nodes so your application can perform file oriented backups and restores Delete the Temporary Snapshot As the last part of the backup process you should delete the temporary snapshot It is no longer needed worsens virtual machine performance and takes up storage space that could be put to better use The Restore Process Your software can follow one of two restore scenarios either revert to a saved state or disaster recovery To bring an existing virtual machine to a previous state 1 Connect to the server and command it to halt and power off the target virtual machine 2 Use the server to gain access to the virtual disks With SAN transport but not HotAdd NBDSSL or NBD you must create a snapshot before restoring data 3 Transfer the disk images from backup using VixDiskLib Revert to and delete the snapshot if created To completely re create a virtual machine disaster recovery 1 Connect to the server 2 Command the server to create a new virtual machine and its virtual disks using the configuration information saved from vim vm ConfigInfo during backup 3 Transfer virtual disk data to the newly created virtual disks using VixDiskLib Virtual disk data includes disk formatting information so you do not need to build an
165. n the section Understanding a PropertySpec on page 66 A TraversalSpec extends SelectionSpec a property of ObjectSpec and contains the following elements Path The element contained in the object that is used to steer traversal m SelectSet An array containing either SelectionSpec or TraversalSpec elements m Skip Whether or not to filter the object in the Path element m Type The type of object being referenced m Name Optional name you can use to reference the TraversalSpec inherited from SelectionSpec SelectionSpec is a direct target for traversal as is TraversalSpec a class extending SelectionSpec It is in the SelectSet that recursion can occur If you wish to traverse the entire configuration tree for a server then you need only the root node moRef which is always a Folder This root folder moRef is available in the property rootFolder of the ObjectSpec service instance content All of the above goes into this Java code sample Traversal objects can use a symbolic name First we define the TraversalSpec objects used to fill in the ObjectSpec This TraversalSpec traverses Datacenter to vmFolder TraversalSpec dc2vmFolder new TraversalSpec dc2vmFolder setTypeC Datacenter Type of object for this spec dc2vmFolder setPath vmFolder Property name defining the next object dc2vmFolder setSelectSet new SelectionSpec folderTSpec This TraversalSpec traverses Datacent
166. nceMode NOTE Selecting maintenance mode does not affect current or pending tasks associated with the vApp Current or pending tasks will run to completion concurrent with the backup or restore operation If these tasks involve configuration changes they could result in an inconsistent vApp configuration The backup system must ensure that such tasks are complete before storing the vApp properties and metadata Associating vCloud Resources with vSphere Entities The admin view of vCloud Director resources provides additional information about the corresponding entities relevant to the vSphere platform This information is available only when administrative credentials are used to log in to vCloud Director The additional information does not replace the use of the vSphere API to provide comprehensive information about the entities It merely provides the bridge between the vCloud and vSphere by mapping the IDs known to the respective systems For example any given virtual machine is known in vCloud Director by a URN that contains the UUID and resource type The same resource is identified in vSphere using its native identification a MoRef Managed object reference Additional information provided in the vCloud API makes the necessary link between the two entities by mapping their ID in the two systems The mapping context is shown in Figure 8 1 Figure 8 1 Mapping to a Virtual Machine from a vApp vCenter Server vCloud Director VM Virtu
167. nment to include the library installation path usr 1ib vmware vix disk1lib 11b64 Makefile The Makefile fetches any packages that are required for compilation but are not installed Library Files Required The virtual disk library comes with dynamic libraries or shared objects on Linux to simplify the delivery of third party and open source components Windows requires the lLib vixDiskLib lib file for linking and the bin d11 files at runtime Linux uses So files for both linking and running Usage Message Running the sample application without arguments produces the following usage message Usage vixdisklibsample command options diskPath commands create creates a sparse virtual disk with capacity specified by cap redo parentPath creates a redo log diskPath for base disk parentPath info displays information for specified virtual disk dump dumps the contents of specified range of sectors in hexadecimal fill fills specified range of sectors with byte value specified by val wmeta key value writes key value entry into disk s metadata table rmeta key displays the value of the specified metada entry meta dumps all entries of the disk s metadata clone sourcePath clone source vmdk possibly to a remote site readbench blocksize do read benchmark on a disk using the specified I O block size in sectors writebench blocksize do write benchmark on disk using the specified I O block size
168. ntivirus software presented in Scan VMDK for Virus Signatures on page 49 for all virtual machines hosted on a VMware Workstation Here is the high level algorithm for an VIX based application that would scan hosted disk on all virtual machines To virus scan hosted virtual disk 1 Write an application including both the Virtual Disk API and the VIX API 2 Initialize the virtual disk library with VixDiskLib_InitQ 3 Connect VIX to the Workstation host with VixHost_Connect 4 Call VixHost_FindItems with item type second argument VIX_FIND_RUNNING_VMS This provides to a callback routine fifth argument the name of each virtual machine one at a time To derive the name of each virtual machine s disk append vmdk to the virtual machine name 5 Write a callback function to open the virtual machine s VMDK Your callback function must be similar to the VixDiscoveryProc callback function shown as an example on the VixHost_FindItems page in the VIX API Reference Guide 6 Instead of printing Found virtual machine in the callback function call the DoVirusScan function shown in Scan VMDK for Virus Signatures on page 49 7 Decontaminate any infected sectors that the virus scanner located The vSphere Web Services API The VMware vSphere Web Services WS API is a developer interface for ESX ESXi hosts and vCenter Server See the VMware developer documentation for information about the vSphere WS API http
169. object also VMware Inc 59 Virtual Disk Programming Guide 60 The data returned from the PropertyCollector is a container class called PropertyFilterUpdate which contains an objectSet with an item by item list of changes to object properties Every item in this container is identified with one of the following keys enter add leave delete and modify On the first data request every data item is included and enter is marked for every data item The PropertyCol lector presents its results in what amounts to random order Since all managed objects have a parent property you can reconstruct the configuration hierarchy by building a tree in memory using the parent identification to organize The root folder is identified as the only folder without a parent Useful Property Information In the data returned from PropertyCol lector you can find most of the information that is useful for backup in the Virtual Machine managed object including the following m Virtual Disks names types and capacities m Virtual Machine Type and Configuration Whatever would be useful in re creating a virtual machine This list might include such information as memory size and number of CPUs m Display Names These names appear in VMware products such as the vSphere Client You should keep track of these names and correlate them for consistency between your product and VMware products VMware supports many virtual disk imple
170. ociated with any snapshot of online virtual machines m Access to VMDK files of offline virtual machines vCenter restricted to registered virtual machines m Reading of Microsoft Virtual Hard Disk VHD format With vCenter Server the Role of the backup appliance when saving data must have these privileges for all the virtual machines being backed up m VirtualMachine gt Configuration gt Disk change tracking m VirtualMachine gt Provisioning gt Allow read only disk access and Allow VM download m VirtualMachine gt State gt Create snapshot and Remove snapshot On the backup appliance the user must have the following privileges m Datastore gt Allocate space m VirtualMachine gt Configuration gt Add new disk and Remove disk m VirtualMachine gt Configuration gt Change resource and Settings The user must have these privileges for vCenter Server and all ESX ESXi hosts involved in backup m Global gt DisableMethods and EnableMethods m Global gt License All privileges must be applied at the vCenter Server level Otherwise the error message returned will be somewhat misleading The host is not licensed for this feature VMware Inc Virtual Disk Interfaces Adapter Types The library can select the following adapters m VIXDISKLIB_ADAPTER_IDE Virtual disk acts like ATA ATAPI PATA SATA and so on You might select this adapter type when it is specifically required by legacy software m VIXDISKLIB_
171. on a supported VMware platform product You may repackage VDDK binaries into your software application after signing a redistribution agreement See the VDDK Release Notes for a list of supported platform products and development systems The VDDK and VADP enable you to develop applications that work effectively across multiple virtual disks from a central location VDDK Components The virtual disk development kit includes the following components m The virtual disk library a set of C function calls to manipulate VMDK files m The disk mount library a set of C function calls to remote mount VMDK file systems m C code samples that can be compiled with Visual Studio or the GNU C compiler m PDF manuals and online HTML reference VMware Inc 11 Virtual Disk Programming Guide Virtual Disk Library VixDiskLib is a standalone wrapper library to help you develop solutions that integrate into VMware platform products The virtual disk library has the following capabilities m Itallows programs to create convert expand defragment shrink and rename virtual disk files m Itcan create redo logs parent child disk chaining or deltas and it can delete VMDK files m It permits random read write access to data anywhere in a VMDK file and reads metadata m Itcan connect to remote vSphere storage using advanced transports SAN or HotAdd For Windows the virtual disk kernel mode driver should be 64 bit User libraries could be 32 bit be
172. on to the list in etc 1d so conf and run ldconfig as the superuser VMware Inc Installing the Development Kit Repackaging VDDK Libraries After you develop an application based on VDDK you might need the VDDK binaries to run your application As described in Redistributing VDDK Components on page 14 partners can sign a license agreement to redistribute VDDK binaries that support VADP applications To enable VDDK binaries on Windows virtual machines without VDDK installed 1 Install the Microsoft Visual C MSVC redistributable possibly as a merge module The latest MSVC runtime works as side by side component so manually copying it might not work on Vista See details on the Microsoft Web site for the redistributable package x86 processors or x64 processors Side by side is also explained on the Microsoft Web site 2 Install VMware executables and DLLs from the bin and 1ib folders of the installed VDDK and the vstor2 mntapil0 sys driver into the Windows system drivers folder or equivalent 3 Create and install your application compiled in a manner similar to the vixDiskLibSamp1e exe code discussed in Chapter 5 Virtual Disk API Sample Code on page 43 How to Find VADP Components ESX ESXi hosts and vCenter Server similarly implement managed objects that support inventory traversal and task requests Before you write VADP software in Java you need to download the vSphere Web Services SDK You can find documentat
173. paceNeededForClone might not give accurate results or could return VIX_E_INVALID_ARG when used with thin provisioned disk type VIXDISKLIB_DISK_VMFS_THIN Clone a Disk by Copying Data This function copies data from one virtual disk to another converting disk type size hardware as specified vixError VixDiskLib_Clone appGlobals connection appGlobals diskPath srcConnection appGlobals srcPath amp createParams CloneProgressFunc NULL TRUE Disk Chaining and Redo Logs In VMDK terminology all the following are synonyms child disk redo log and delta link From the original parent disk each child constitutes a redo log pointing back from the present state of the virtual disk one step at a time to the original This pseudo equation represents the relative complexity of backups and snapshots backup image lt child disk redo log delta link lt snapshot A backup image such as on magnetic tape is less than a child disk because the backup image is merely a data stream A snapshot is more than a child disk because it also contains the virtual machine state with pointers to associated file system states on VMDK There exist other types of redo log such as those that perform progressive protection in vSphere Replication VR For disk chaining the redo terminology is especially appropriate for the snapshot revert operation when changed blocks in the redo log are applied to the base disk before deleting the redo log
174. pectively This chapter focuses on the protection provided at the system level where service providers can employ backup solutions from vendors of data protection software This chapter describes how to design software to back up and restore the vApps in a vCloud To back up or restore a vApp you need to deal with both the vCloud configuration and the virtual machines that belong to the vApp In vSphere a virtual machine is represented by configuration files and virtual disk files Prerequisites You should be familiar with programming concepts and techniques You should also be familiar with vCloud vCloud API vCloud SDK for NET and vSphere concepts VMware also provides the vCloud SDK for Java and the vCloud SDK for PHP but this chapter focuses on NET for the backup and restore examples VMware recommends that you design backup and restore software for the vCloud environment using the following APIs Table 1 APIs Used To Back Up vApps Product API Data vCloud Director vCloud API or vCloud SDK wrapper vApp metadata vSphere WS API virtual machine configuration VDDK VixDiskLib API or VixMntapi virtual disk contents You use the vCloud API or SDK to identify vApp targets for backup and restore operations The vApp metadata identifies the virtual machines that constitute the vApp You use the WS API to back up and restore virtual machine configurations You use the VDDK API to back up and restore virtual disk files NOTE Thi
175. phere Backup on page 39 VMware Inc 33 Virtual Disk Programming Guide Redo Logs and Linked Clone Backup For managed virtual disk on vSphere snapshots are used primarily for saving system state and for backup while linked clones create duplicate images for provisioning of View desktops A snapshot is usually a single redo log in a parent child chain while linked clones are usually multiple redo logs based on the same parent In the vSphere 5 5 release the handling of linked clone hierarchies was changed to improve the efficiency of backup and restore The disk object now contain a disk backing that contains one or more parent backing objects until the base disk is reached This allows access anywhere in the parent child disk chain With a clean never used base virtual machine the linked clone hierarchy or snapshot chain always has the proper number of parent backing objects for the nodes in the chain VDDK does not contain any convenience interfaces for backing up and restoring the linked clone hierarchy or the snapshot chain Backup applications are responsible for discovering and saving the hierarchy if they want to support this as a feature In VMware View VDI environments linked clone backup might not be necessary or advisable especially for nonpersistent desktops that revert to default after use When the base disk or a child disk has an extra snapshot when redo logs used to create linked clones were never deleted
176. powered off that guest OS becomes unbootable Renaming a Disk The function to rename virtual disk files is VixDiskLib_Rename It takes two arguments the old and the new VMDK filenames vixError VixDiskLib_Rename oldGlobals diskpath newGlobals diskpath 52 VMware Inc Practical Programming Tasks Effects of Renaming a Virtual Disk The server expects VMDK files of its guest OS virtual machines to be ina predictable location Any file accesses that occur during renaming might cause I O failure and possibly cause a guest OS to fail Working with Disk Metadata With VMFS on ESX ESXi hosts disk metadata items could be important because they store information about the disk mapping and interactions with the containing file system Managing Child Disks In the Virtual Disk API redo logs are managed as a parent child disk chain each child being the redo log of disk changes made since its inception Trying to write on the parent after creating a child results in an error The library expects you to write on the child instead See Figure 4 2 Child Disks Created from Parent on page 33 for a diagram Creating Redo Logs A redo log is created by taking a virtual machine snapshot which contains both disk data and virtual machine state On hosted disk only VixDiskLib_CreateChild creates a redo log without virtual machine state You could write a simple application to create redo logs or snapshots on managed disk at 3 00
177. products including VMware Workstation are neither tested nor supported Storage Device Support VMware Consolidated Backup VCB had knowledge base article http kb vmware com kb 1007479 showing the support matrix for storage devices and multipathing VMware does not provide a similar support matrix for VDDK and VADP Customers must get this information from you their backup software vendor Installing the VDDK Package The VDDK is packaged as a compressed archive for Windows 64 bit and for Linux 64 bit The VDDK packages include the following components m Header files vixDiskLib h and vm_basic_types h in the include directory m Function library vixDiskLib 1ib Windows or libvixDiskLib so Linux in the lib directory m HTML reference documentation in the doc directory and sample program in doc samples V CAUTION In the VDDK 5 5 release VMware has discontinued the Windows installer and 32 bit executables for Windows and Linux For Windows the VDDK is delivered as a ZIP archive for 64 bit systems only 16 To install the package on Windows 1 On the Download page choose the zip file for Windows and download it to your development system 2 Place the zip file in a folder under Program Files you can choose the name and unpack it cd C Program Files VMware VDDK550 unzip VMware vix diskLib zip 3 Goto the bin subfolder locate the vstor2instal1 bat script and double click to run it The batch script should be r
178. release 2009 05 29 Final version for the VDDK 1 1 public release 2008 04 11 Updated version for release 1 0 of the Virtual Disk Development Kit 2008 01 31 Initial version of the Virtual Disk Development Kit for partner release Intended Audience This guide is intended for developers who are creating applications that manage virtual storage especially backup and restore applications It assumes knowledge of C and C programming For VADP development this guide assumes knowledge of Java VMware Inc Virtual Disk Programming Guide Supported Platform Products You can develop VDDK programs using either Linux or Windows and test them using VMware Workstation or ESXi and vSphere To develop and test VADP programs you need a vCenter Server and ESXi hosts preferably with shared cluster storage Document Feedback VMware welcomes your suggestions for improving our developer documentation Send your feedback to docfeedback vmware com VMware Technical Publications VMware Technical Publications provides a glossary of terms that might be unfamiliar to you For definitions of terms as they are used in VMware technical documentation go to http www vmware com support pubs To access the current versions of VMware manuals go to http pubs vmware com vsphere 50 index jsp 10 VMware Inc Introduction to the Virtual Disk API This chapter presents the following topics m About the Virtual Disk API on page 11 m VDDK
179. returned by VixMntapi_GetVoLumeInfo For example VixVolumeInfo symbolicLink obtained using VixMntapi_GetVoLumeInfo is the path on the proxy where you can access the virtual disk s file system using ordinary open read and write calls Once you are done accessing files in a mounted volume there are VixMntapi procedures for taking down the abstraction that you created These calls are m VixMntapi_DismountVoLume for each volume handle m VixMntapi_FreeOsInfo and VixMntapi_FreeVoLumeInfo m VixMntapi_CloseDiskSet This leaves the VixDiskLib handles that you obtained in the beginning you must dispose of them properly VMware Inc 63 Virtual Disk Programming Guide More VADP Details The preceding sections explained how to contact vSphere and extract information from it and how to back up or restore virtual disks The following sections cover the same information at a lower level Low Level Backup Procedures 64 This section describes low level details that may be helpful in coding a backup application It is not the intent of this material to impose a design but only to serve as a guideline with examples and exposition The code samples provided below are not complete They generally lack error handling and ignore critical details Communicating with the Server Connections to the server machine require credentials user name password and host name or IP address The following code connects to the server and extr
180. revious snapshots read only On Linux virtual machines before VDDK 5 5 you could not mount previous snapshots in the chain If you specify a virtual disk with snapshots on a powered off virtual machine VixMntapi locates and mounts the last snapshot in the disk chain While a disk is mounted do not revert to a previous snapshot using another VMware interface this would make it impossible to unmount the partition You cannot mount virtual disk if any of its vmdk files are encrypted compressed or read only However you can change these attributes and then mount the virtual disk With Windows you must mount virtual disks on drive D or greater and choose a drive letter not in use With Linux kernel version 2 6 or higher is required to run the FUSE file system in user space module You cannot mount Linux swap or extended partitions Logical Volume Manager LVM is not supported You can mount Windows virtual disks on Windows hosts with an NTFS volume or Linux virtual disks on Linux hosts Cross mounting is restricted but may be allowed for cross formatted file systems 109 Virtual Disk Programming Guide 110 VMware Inc Errors Codes and Open Source This appendix contains the following sections m Finding Error Code Documentation on page 111 Troubleshooting Dynamic Libraries on page 111 m Open Source Components on page 112 Finding Error Code Documentation For a list of Virtual Disk API error codes s
181. rocedures 73 Restoring a Virtual Machine and Disk 73 Creating a Virtual Machine 74 Using the VirtualMachineConfigInfo 79 Editing or Deleting a Device 80 VMware Inc Restoring Virtual Disk Data 80 Raw Device Mapping RDM Disks 80 Restore of Incremental Backup Data 80 Restore Fails with Direct Connection to ESXi Host 81 Tips and Best Practices 81 Best Practices for SAN Transport 81 Best Practices for HotAdd Transport 82 Best Practices for NBDSSL Transport 82 General Backup and Restore 83 Backup and Restore of Thin Provisioned Disk 83 Virtual Machine Configuration 83 About Changed Block Tracking 83 HotAdd and SCSI ControllerIDs 84 Windows Backup Implementations 84 Working with Microsoft Shadow Copy 84 Application Consistent Backup and Restore 85 The VMware VSS Implementation 86 8 Backing Up vApps in vCloud Director 87 Introduction to Tenant vApps 87 Prerequisites 88 Other Information 88 Conceptual Overview 88 The Backup Process 89 The Restore Process 89 Use Cases Overview 90 Managing Credentials 90 Finding avApp 91 Inventory Traversal 91 Using the Query Service 91 Protecting Specified vApps 91 Recovering an Older Version ofavApp 91 Recovering a Deleted vApp 91 Recovering a Single Virtual Machine 91 Backing Up vCloud Director 91 vCloud API Operations 92 Getting Access to vCloud Director 92 Inventory Access 92 Admin Views 93 Admin Extensions 93 Retrieving Catalog information 96 Retrieving vApp Configuration 97 Methods To Retri
182. rtual disk on local storage subsequent writes will fail In this case the program should explicitly pass nbd or nbdss1 as the preferred transport mode VMware Inc 37 Virtual Disk Programming Guide In the connection parameters cnxParams the vmxSpec managed object reference would be different on an ESX ESXi host than on the vCenter Server vmxSpec moid 23498 vmxSpec moid 898273 The port should be the one on which vCenter Server listens for API queries Specifying a null port allows the library to select the default communications port It is likely to be 443 HTTPS or maybe 902 VIX automation This is the port for data copying not the port for SOAP requests Get Selected Transport Method The VixDiskLib_GetTransportMode function returns the transport method selected for diskHandle printfC Selected transport method s n VixDiskLib_GetTransportMode diskHand1le Prepare For Access and End Access The VixDiskLib_PrepareForAccess function notifies a vCenter managed host that a virtual machine s disks are being opened probably for backup so the host should postpone virtual machine operations that might interfere with virtual disk access Call this function before creating a snapshot on a virtual machine Internally this function disables the vSphere API method RelocateVM_Task vixError VixDiskLib_PrepareForAccess amp cnxParams vmName The connection parameters must indicate one virtual machine only W
183. rtyCollector capture configuration VirtualMachineConfigInfo and changed block information with queryChangedDiskAreas Save these for later m Using advanced transport functions and VixDiskLib access the snapshot and save the data in it If Changed Block Tracking is enabled the snapshot contains only incremental backup data VMware Inc 39 Virtual Disk Programming Guide 40 m Ask the ESX ESXi host to delete the backup snapshot A typical back in time disaster recovery or file based restore follows this algorithm m Preferably through VMware vCenter contact the ESX ESXi host containing the target virtual machine m Ask the ESX ESXi host to halt and power off the target virtual machine m Using advanced transport functions restore a snapshot from saved backup data m For disaster recovery to a previous point in time have the virtual machine revert to the restored snapshot For file based restore mount the snapshot and restore requested files Chapter 7 Designing vSphere Backup Solutions on page 57 presents these algorithms in more detail and includes code samples Backup and Recovery Example The VMware vSphere API method queryChangedDiskArea returns a list of disk sectors that changed between an existing snapshot and some previous time identified by a change ID The queryChangedDiskAreas method takes four arguments including a snapshot reference and a change ID It returns a list of disk sectors that changed betw
184. s ReferenceType organizationReference organizationsMap organizationName Organization org Organization GetOrganizationByReference client organizationReference string OrgID org Resource id Console WriteLineC Organization Name organizationName Console WriteLineC Organization Id OrgID foreach ReferenceType orgRef in organizationsMap Values Organization org Organization GetOrganizationByReference client orgRef foreach ReferenceType vdcRef in org GetVdcRefs Vdc vdc Vdc GetVdcByReference client vdcRef string vdcId vdc Resource id Console WriteLine Org vDC Id vdcId Console WriteLine Org vDC Name vdc Reference name foreach ReferenceType vAppRef in Vdc GetVdcByReference client vdcRef GetVappRefs Vapp vapp Vapp GetVappByReference client vAppRef Console WriteLine vApp Id vapp Resource id Console WriteLine vApp Name vapp Resource name List lt VM gt vms new List lt VM gt try vms vapp GetChildrenVms catch Handle exception here foreach VM vm in vms Console WriteLine VM Id vm Resource id Console WriteLine VM Name vm Resource name J 94 VMware Inc Backing Up vApps in vCloud Director The NET SDK code in Example 8 5 translates to the API calls shown in Example 8 6 Example 8 6 REST API Calls To List vApps in a VDC for a Given Organization GET https vCloud api admin GET https v
185. s and to have other worker threads doing reads and writes This diagram shows concurrent reads on two separate disk handles Concurrent reads on the same disk handles are not allowed Open Close Thread VixDiskLib_Open VixDiskLib_Open VixDiskLib_Close VixDiskLib_Close Chand1le1 Chand1e2 Chand1le1 Chand1le2 I O Thread 1 Cowns handle1 VixDiskLib_Read VixDiskLib_Read I O Thread 2 Cowns handle2 VixDiskLib_Read VixDiskLib_Read 41 Virtual Disk Programming Guide Capabilities of Library Calls 42 This section describes limitations if any Support for Managed Disk Some operations are not supported m ForVixDiskLib_Connect to open a managed disk connection you must provide valid vSphere access credentials On ESX ESXi hosts VixDiskLib_Open cannot open a single link in a disk chain m For VixDiskLib_Create to create a managed disk on an ESX ESXi host first create a hosted type disk then use VixDiskLib_Clone to convert the hosted virtual disk to managed virtual disk m VixDiskLib_Defragment can defragment hosted disks only m VixDiskLib_Grow can grow hosted disks only m VixDiskLib_Unlink can delete hosted disks only m Until ESXi 5 1 the HotAdd transport was available only with vSphere Enterprise Edition and higher Support for Hosted Disk Most everything except advanced transport is supported except m The VixDiskLib_ConnectEx extended connect functio
186. s chapter uses the term metadata in a general sense to mean all the vApp configuration data in addition to user defined data that the vCloud REST API serializes in the lt Metadata gt element You should be familiar with the use of the WS API and the VDDK API for backup and restore of individual virtual machines Other Information This chapter does not in general duplicate information available in other documents In particular this chapter does not provide details about any storage or data protection API that you need to use for backing up and restoring virtual machines in vSphere You should consult separate reference documentation for details about specific API calls This chapter emphasizes the use of the vCloud API and SDK for the purpose of managing metadata of the virtual machines and related artifacts in vCloud Director The vCloud SDK for NET translates your C code into REST operations using the vCloud API To learn about VMware vCloud and vSphere concepts and usage refer to the vCloud Director documentation available from the VMware Web site http www vmware com support sdk_pubs html You can also visit the VMware SDK community forum at http communities vmware com community vmtn Conceptual Overview 88 This section summarizes the backup and restore processes for vApps managed by vCloud Director It explains how to use VMware APIs to collect the metadata needed to control backup and restore operations The actual b
187. serial port settings in the nvram file and possibly other items so applications should back up and restore this information VMware Inc Practical Programming Tasks To back up and restore NVRAM 1 For each virtual machine make a separate copy of the nvram file 2 Back up each virtual machine using standard methods 3 If necessary restore the virtual machine using standard methods 4 Overwrite the virtual machine s nvram file with the saved copy of the original nvram file IMPORTANT VMware now recommends saving the nvram file as part of virtual machine backup a change in recommendation since vSphere 4 1 Interfacing With VMware vSphere This section provides pointers to other vSphere programming interfaces The VIX API The VIX API is a popular easy to use developer interface for VMware Workstation other hosted products and ESX ESXi See the VMware developer documentation for information about the VIX API http www vmware com support developer vix api The VIX API Reference guide includes function reference pages for C Perl and COM component object model for Microsoft C VBScript and Visual Basic Most reference pages include helpful code examples Additionally the vix api Web guide includes examples for power on and off suspending a virtual machine taking a snapshot guest operations virtual machine discovery and asynchronous callbacks Virus Scan all Hosted Disk Suppose you want to run the a
188. skLib_Disconnect srcConnection VixDiskLib_ExitQ VMware Inc 69 Virtual Disk Programming Guide Deleting a Snapshot When you are done performing a backup you need to delete the temporary snapshot You can get the moRef for the snapshot from taskRef info result as describe above for the create snapshot operation The following Java code demonstrates how to delete the snapshot ManagedObjectReference removeSnapshotTask ManagedObjectReference snapshot Already initialized removeSnapshotTask serviceConnection getservice removeSnapshot_Task snapshot Boolean FALSE Changed Block Tracking on Virtual Disks On hosts running ESX ESXi 4 0 and later virtual machines can keep track of disk sectors that have changed This is called changed block tracking Its method in the VMware vSphere API is QueryChangedDiskAreas which takes the following parameters m _this Managed object reference to the virtual machine m snapshot Managed object reference to a Snapshot of the virtual machine m deviceKkey Virtual disk for which to compute the changes m startOffset Byte offset where to start computing changes to virtual disk The length of virtual disk sector s examined is returned in DiskChangeInfo m changeld An identifier for the state of a virtual disk at a specific point in time A new ChangelId results every time someone creates a snapshot You should retain this value with the version of change data that you extr
189. skLib_Write newDisk HandleQ i j buf Close a Local or Remote Disk VixDiskLib_Close closes an open virtual disk VixDiskLib_Close srcHandle Get Information About a Disk vixError VixDiskLib_GetInfo srcHandle diskInfo VixDiskLib_GetInfo gets data about an open virtual disk allocating a filled in VixDiskLibDiskInfo structure Some of this information overlaps with metadata see Metadata Handling on page 31 VMware Inc Virtual Disk API Functions Free Memory from Get Information This function deallocates memory allocated by VixDiskLib_GetInfo Call it to avoid a memory leak vixError VixDiskLib_FreeInfo diskInfo Error Handling These functions enhance the usefulness of error messages Return Error Description Text VixDiskLib_GetErrorText returns the textual description of a numeric error code char msg VixDiskLib_GetErrorText errCode NULL Free Error Description Text VixDiskLib_FreeErrorText deallocates space associated with the error description text VixDiskLib_FreeErrorText msg Metadata Handling VMware provides a mechanism for virtual disk metadata but it is seldom used Read Metadata Key from Disk vixError VixDiskLib_ReadMetadata disk Handle appGlobals metaKey amp val 0 requiredLen NULL Retrieves the value of a given key from disk metadata The metadata for a hosted VMDK is not as extensive as for managed disk on an ESX ESXi host Held in a mapping file VMF
190. skSet The VixDiskLibHandle type defined in vixDiskLib h is the same as for the diskHand1e parameter in the VixDiskLib_Open function but here it is an array instead of a single value Parameters m diskHandles in Array of handles to open disks m numberOfDisks in Number of disk handles in the array m openMode in Must be 0 zero m diskSet out Disk set handle to be filled in If you want to mount disks on a Windows system first call VixDiskLib_Open for every disk then use the returned disk handle array to call VixMntapi_OpenDiskSet which returns a disk set handle If you want to mount disks on a Linux system call the function VixMntapi_OpenDisks which opens and creates the disk set handle all in one function VixMntapi_OpenDisks Opens disks for mounting on a Linux virtual machine or disk sets on a Windows virtual machine On Linux the Logical Volume Manager LVM is not yet supported VixError VixMntapi_OpenDisks VixDiskLibConnection connection const char diskNames size_t numberOfDisks uint32 openFlags VixDiskSetHandle handle Parameters m connection in The VixDiskLibConnection to use for opening the disks Calls VixDiskLib_Open with the specified flags for each disk to open m diskNames in Array of disk names to open m numberOfDisks in Number of disk handles in the array Must be 1 for Linux m flags in Flags to open the disk m handle out Disk set handle to be
191. st while srcConnection and appGlobals srcPath represent the local hosted VMDK 4 Power on the new guest OS to get a new virtual machine On Workstation the VixVMPowerOn function in the VIX API does this For ESX ESXi hosts you must use the PowerOnVM_Task method As easy way to use this method is in the VMware vSphere Perl Toolkit which has the PowerOnVM_Task call non blocking and the PowerOnVM call synchronous 5 Provision and deploy the new virtual machine on the ESX ESXi host Special Consideration for ESX ESXi Hosts No matter what virtual file type you create in Step 1 it becomes type VIXDISKLIB_DISK_VMFS_FLAT in Step 3 VMDK File Versions Virtual disk programs must be able to cope with VMDK files up to version three 3 Version 1 was the initial version of VMDK All released builds of vixDiskLib can read and write this version Version 2 added disk encryption for hosted products Workstation and Fusion although encrypted disks were never implemented on ESX ESXi Version 2 VMDK files can be transferred to and appear on ESX ESXi where they are treated like version 1 VMDK files Version 3 added support for persistent changed block tracking CBT and is set when CBT is enabled for a virtual disk This version first appeared in ESX ESXi 4 0 and continues unchanged in recent ESXi releases When CBT is enabled the version number is incremented and decremented when CBT is disabled If you look at the vmdk descriptor fi
192. t created From this snapshot moRef you can extract the disk names and paths How to do this is demonstrated in section Backing Up a Virtual Disk on page 69 To read the data in a virtual disk it is necessary to use the VixDiskLib This library isolates the programmer from the details of extracting data from a virtual disk and its redo logs For example when doing backup you call functions VixDiskLib_Open and VixDiskLib_Read among others VixDiskLib allows access to disk data on sector boundaries only the transfer size is some multiple of the disk sector size When accessing disks on ESXi hosts VixDiskLib release 1 0 transferred virtual disk data over the network Later VixDiskLib releases contain API enhancements so you can request more efficient data paths such as direct SAN access or HotAdding disks to a virtual backup appliance These efficient data paths requires minor code changes such as calling VixDiskLib_ConnectEx instead of plain connect Part of virtual disk information is metadata a number of key value pairs describing configuration of the virtual disk Metadata information can be extracted from a virtual disk using the VixDiskLib functions VixDiskLib_GetMetadataKeys and VixDiskLib_ReadMetadata You should save metadata keys along with the backup in case you need to re create the virtual disk The VixDiskLib API allows a backup application to perform a full backup of a virtual machine The newer VixMntapi library ca
193. talogs and Catalog Items for a Given Organization Console WriteLine if CorganizationsMap null amp amp organizationsMap Count gt 0 foreach string organizationName in organizationsMap Keys ReferenceType organizationReference organizationsMap organizationName Console WriteLine organizationName Console WriteLine organizationReference href Organization organization Organization GetOrganizationByReference client organizationReference List lt ReferenceType gt catalogLinks organization GetCatalogRefs if catalogLinks null amp amp catalogLinks Count gt 0 foreach ReferenceType catalogLink in catalogLinks Catalog catalog Catalog GetCatalogByReference client catalogLink CatalogType catalogType catalog Resource Console WriteLine catalogType name Console WriteLine catalogLink href List lt ReferenceType gt catalogItemReferences catalog GetCatalogItemReferences if catalogItemReferences null amp amp catalogItemReferences Count gt 0 foreach ReferenceType catalogItemReference in catalogItemReferences Console WriteLine Console WriteLine catalogItemReference name catalogItemReference href Console WriteLineQ else Console WriteLine No CatalogItems Found Console WriteLineQ else Console WriteLine No Catalogs Found else Console WriteLine No Organizations VMware Inc
194. tents moving data to lower numbered extents and is independent of defragmentation tools in the guest OS such as Disk gt Properties gt Tools gt Defragmentation in Windows or the defrag command for the Linux Ext2 file system VMware recommends defragmentation from the inside out first within the virtual machine then using this function or a VMware defragmentation tool and finally within the host operating system VMware Inc Virtual Disk API Functions Shrink an Existing Local Disk VixDiskLib_Shrink reclaims unused space in an existing virtual disk unused space being recognized as blocks of zeroes This is more effective gains more space with SPARSE type files than with pre allocated FLAT type On success the function returns VIX_OK This function supports hosted disk but not managed disk vixError VixDiskLib_Shrink disk Handle Q ShrinkProgressFunc NULL In VMware system utilities prepare zeros out unused blocks in the VMDK so shrink can reclaim them In the API use VixDiskLib_Write to zero out unused blocks and VixDiskLib_Shrink to reclaim space Shrink does not change the virtual disk capacity but it makes more space available Unlink Extents to Remove Disk VixDiskLib_Unlink deletes all extents of the specified virtual disk which unlinks removes the disk data This is similar to the remove or erase command in a command tool vixError VixDiskLib_Unlink appGlobals connection appGlobals d
195. ter TRUE oo ON D oO A Click OK and click Save 10 Power on the virtual machine Application consistent quiescing is available for this virtual machine after the UUID property is enabled Application Consistent Backup and Restore Here is the approximate procedure for software to performs application consistent backup and restore 1 Call CreateSnapshot_task with the quiescent flag set true 2 Open the leaf node of the disk with VDDK and read both the base VMDK and the snapshot at once 3 Delete the snapshots created in the first step 4 During restore create a new virtual machine 5 Write the VMDK to disk with VDDK It should have both base and quiesced information VMware Inc 85 Virtual Disk Programming Guide 86 During backup if the snapshot was created with quiesce flag set to true and all the quiescing conditions are met so the snapshot is created involving VSS and the snapshot disks represent application consistent state of the guest OS You should be able to confirm this by downloading the VSS manifest zip file unzipping it to check if it has just the backup component document in which case file system quiescing was performed or also writer manifests in which case application quiescing was performed Quiescing involves the VSS mechanism designed by Microsoft So regarding VSS backup restore verification refer to the VSS documentation provided by Microsoft VMware helps by providing a vss manifest zip file that cont
196. tive path rather than absolute path so conflicting versions of the DLLs could cause problems Visual C on Windows To compile the program find the sample source vixDiskLibSamp1Le cpp at this location C Program Files VMware VMware Virtual Disk Development Kit doc sample For VDDK 5 5 and later make sure that you have the 64 bit debugging tools installed along with Visual Studio Double click the vcproj file possibly convert format to a newer version and choose Build gt Build Solution To execute the compiled program choose Debug gt Start Without Debugging or type this in a command prompt after changing to the doc samp1e location given above Debug vixdiskLibsampLe exe SLN and VCPROJ Files The Visual Studio solution file vixDiskLibSample s1n and project file vixDiskLibSample vcproj are included in the sample directory VMware Inc 43 Virtual Disk Programming Guide C on Linux Systems Find the sample source in this directory usr share doc vmware vix disklib samples diskLib You can copy vixDiskLibSample cpp and its Makefile to a directory where you have write permission or switch user to root On some Linux systems you need to add incLude statements for lt stdio h gt and lt string h gt after the e1se clause on line 15 Type the make command to compile Run the application make vix diskLib sampLe NOTE If this fails edit etc 1d so conf and run ldconfig as root or change your LD_LIBRARY_PATH enviro
197. tors containing virtual disk data Default size is 128 sectors or 64KB Data Structures in Virtual Disk API Here are important data structure objects with brief descriptions m VixError Error code of type uint64 VixDiskLibConnectParams Public types designate the virtual machine credentials vmxSpec possibly through vCenter Server the name of its host and the credential type for authentication For details see VMX Specification on page 29 The credType can be VIXDISKLIB_CRED_UID user name password most common VIXDISKLIB_CRED_SESSIONID the HTTP session ID VIXDISKLIB_CRED_TICKETID vSphere ticket ID or VIXDISKLIB_CRED_SSPI Windows only current thread credentials typedef char vmxSpec typedef char serverName typedef VixDiskLibCredType credType m VixDiskLibConnectParams VixDiskLibCreds Credentials for either user ID or session ID VixDiskLibConnectParams VixDiskLibCreds VixDiskLibUidPasswdCreds String data fields represent user name and password for authentication VixDiskLibConnectParams VixDiskLibCreds VixDiskLibSessionIdCreds String data fields represent the session cookie user name and encrypted session key VMware Inc 21 Virtual Disk Programming Guide 22 VixDiskLibConnectParams VixDiskLibCredsb VixDiskLibSSPICreds String data fields represent security support provider interface SSPI authentication User name and password are null m VixDiskLibCreateParams Typ
198. tory lt unset gt preserveSwapOnPowerOff lt unset gt bootOptions vim vm BootOptions null appliance vim vService ConfigSpec null ftInfo vim vm FaultToleranceConfigInfo null applianceConfigRemoved lt unset gt vAssertsEnabled lt unset gt changeTrackingEnabled lt unset gt end of VirtualMachineConfigSpec The information above is quite complex but much of the input consists of defaulted values that are assigned by the system The remainder of the supplied information can be extracted from the output of the config hardware device table returned from PropertyCollector Borrowing heavily from an SDK code example the following code sets up the configuration specification Duplicate virtual machine configuration VirtualMachineConfigSpec configSpec new VirtualMachineConfigSpec Set the VM values configSpec setName My New VM configSpec setVersionC vmx 04 configSpec setGuestIdC winNetStandardGuest configSpec setNumCPUs 1 configSpec setMemoryMB 256 Set up file storage info VirtualMachineFileInfo vmfi new VirtualMachineFileInfoQ vmfi setVmPathName pLat004 Local configSpec setFiles vmfi vmfi setSnapshotDirectory plat004 Local Set up tools config info ToolsConfigInfo tools new ToolsConfigInfo configSpec setTools tools tools setAfterPowerOn new Boolean true tools setAfterResume new Boolean true tools setBeforeGuestStandby new
199. tual machines that belong to the vApp The admin view provides information such as Managed Object References that vCenter uses for those entities See Associating vCloud Resources with vSphere Entities on page 99 for more information about getting vCenter Managed Object References To access admin views you use a method of the client connection object to create an admin client proxy The admin proxy has methods similar to those of the client connection object to get references to Organizations and other vCloud objects However the objects you get from the admin proxy have additional properties not present in user objects Admin Extensions Similar to the admin views you can use a different method of the client connection object to create an admin extension client proxy You use the admin extension proxy to find provider VDC A provider VDC includes one or more resource pools and allocates resources from those pools to the Org VDCs that it supports Example 8 3 shows how to get a Provider VDC Example 8 3 Get Provider VDC Login Get dictionary of Provider vDCs AdminExtension VcLoudAdminExtension adminExt client GetVcloudAdminExtension string pvdcName ProvVDC1 Dictionary lt string ReferenceType gt refs adminExt GetVMWProviderVdcRefsByName Get reference for pvdcName gt pvdcRef ReferenceType pvdcRef refs pvdcName VMWProviderVdc vmwPvdc VMWProviderVdc GetVMWProviderVdcByReference client pvdcRe
200. tualMachine is a child of ResourcePool which controls the sharing of a physical machine s resources among VirtualMachine objects A ComputeResource contains an item named resourcePool which is a moRef to a ResourcePool m VirtualApp A VirtualApp vApp is a collection of VirtualMachines that make up a single application This is a special form of ResourcePool defined below A VirtualApp may have three types of children m VirtualMachine A folder named vm contains a list of moRefs to child VirtualMachines m resourcePool A folder containing a list of moRefs pointing to child ResourcePools or VirtualApps m VirtualApp A VirtualApp can be composed of other VirtualApps m ResourcePool You can segment the resources of a VirtualApp using a ResourcePool m ResourcePool This managed object contains two child items m resourcePool A folder containing a list of moRefs pointing to child ResourcePools or VirtualApps m vm A list of moRefs to child VirtualMachines that employ the resources of the parent ResourcPool A VirtualMachine always lists a ResourcePool as its parent m VirtualMachine The VirtualMachine is often considered an end object so you do not need to describe any traversal for this object The ObjectSpec does not have to lead you any farther than the moRef of a target object You can gather information about the managed object itself using the moRef and the PropertySpec This is described in detail i
201. u need to begin VDDK and VADP development Development Systems The VDDK has been tested and is supported on the following systems m Windows 64 bit x86 64 systems m Linux 64 bit x86 64 systems See the VDDK Release Notes for specific versions which change over time Mac OS X is not supported Programming Environments You can compile the sample program and develop vSphere applications in the following environments Visual Studio on Windows On Windows programmers can use the C compiler in Visual Studio 2005 Visual Studio 2008 and later Along with Visual Studio you also need to install the 64 bit debugging tools C and C on Linux On Linux programmers can use the GNU C compiler version 4 and higher The sample program compiles with the C compiler g but VDDK also works with the C compiler gcc Java Development for VADP When developing backup and restore software to run on vSphere VMware recommends Eclipse with Java on both Windows and Linux The vSphere Web Services SDK now includes both Axis and JAX WS bindings You can call C or C code with wrapper classes as in Java Native Interface JNI VMware Platform Products Software applications developed with the VDDK and VADP target the following platform products m vCenter Server managing ESXi hosts m ESXi hosts directly connected VMware Inc 15 Virtual Disk Programming Guide See the VDDK Release Notes for specific versions which change over time Hosted
202. ual machine Using the vSphere Web Services API it is possible to back up all the virtual disks associated with a virtual machine The handling of the vCenter or an individual ESXi host is essentially equivalent when using the vSphere SDK With vCenter management there is no need to contact individual ESXi hosts directly The remainder of this chapter uses the term vSphere to indicate either a vCenter Server or an ESXi host To reduce the resources used by vSphere VMware recommends that the number of connections or Sessions be minimized It is in the best interests of any program that communicates with vSphere to create one Session and share it with all elements of the program that need to exchange information with vSphere This means that if your program supports multiple threads your program should multiplex the use of connection objects by use of access control locks mutex and the like It is also important that all vSphere SDK operations proceed from one instance of the Session object that your application requests after logging into vSphere Using the vSphere API your application can create objects that are Session specific and therefore would not be known to other portions of your application that might use a different Session Information Containers as Managed Objects VMware documentation introduces you to the concept of the managed object and its handle called amanaged object reference moRef You might be tempted to get
203. un in place so that the current directory for execution is the bin subfolder By running it you implicitly accept the VMware license terms 4 Edit the Windows registry with regedit and check for the following key If this key exists from a previous VDDK install right click to delete it Add a registry entry with the following key HKEY_LOCAL_MACHINE SOFTWARE Wow6432Node VMware Inc VMware Virtual Disk Development Kit 5 Tothis key add a DWORD value named VerifySSLCertificates setting it to 1 if you want SSL certificates to be validated or 0 if you want to prevent SSL certificates from being validated For convenience you might want to edit the Windows Path environment to include the VDDK installation folder C Program Files VMware VDDK550 bin in the example above To Install the package on Linux 1 On the Download page choose the binary tar gz for 64 bit Linux 2 Unpack the archive with tar to create the vmware vix disklib distrib subdirectory tar xvzf VMware vix disklib tar gz 3 Change to that directory and run the installation script as the superuser cd vmware vix disk1lib distrib sudo vmware instaLL plL 4 Read the license terms and type yes to accept them Software components install in usr unless you specify otherwise You might want to edit your LD_LIBRARY_PATH environment to include the library installation path usr 1lib vmware vix disklib 11b64 for instance Alternatively you can add the library locati
204. use sectors of the disk change 1 change 0 change 0 All sectors altered since change 0 Wa The following restrictions are imposed on the query when determining allocated areas of a virtual disk m The disk must be located on a VMFS volume backing does not matter m The virtual machine must have had no zero snapshots when changed block tracking was enabled 70 VMware Inc Designing vSphere Backup Solutions Enabling Changed Block Tracking This feature is disabled by default because it reduces performance by a small but measurable amount If you query the virtual machine configuration you can determine if it is capable of changed block tracking Use the property collector to retrieve the capability field from the VirtualMachineManagedObject If the capability field contains the flag changeTrackingSupported then you can proceed The virtual machine version must be 7 or higher to support this If the virtual machine version is lower than 7 upgrade the virtual hardware If supported you enable changed block tracking using an abbreviated form of VirtualMachineConfigSpec then use the ReconfigVM_Task method to reconfigure the virtual machine with changed block tracking VirtualMachineConfigSpec configSpec new VirtualMachineConfigSpec configSpec changeTrackingEnabled new Boolean true ManagedObjectReference taskMoRef serviceConnection getService ReconfigVm_Task targetVM_MoRef configSpec Powered on virtual ma
205. virtual machines One VMFS partition is supported for each SCSI storage device or LUN VMX virtual machine configuration file A file containing a virtual machine s configuration This vmx file is created with its virtual machine and is used to identify and run a specific virtual machine 114 VMware Inc Index Numerics 32 bit and 64 bit 12 A access and credentials 22 application consistent quiescing Windows 85 B backing information for virtual disk 68 backup algorithms 40 backup process overview of 57 best practices for SAN transport 81 BIOS customizations saving 54 c change ID 40 changed block tracking CBT 51 70 code sample walk through 45 configFile settings for VixDiskLib_InitEx 36 CopyThread 46 48 credentials and access 22 D development platforms 15 differential backup 40 disassociate host from vCenter Server 81 disaster recovery 40 disk mount vmware mount 12 E eager zeroed thick disk 20 83 error codes finding explanations for 111 ESX ESXi and VMware vCenter 11 22 extent 19 34 50 113 F flat VMDK 19 20 31 34 113 G gcc GNU C compiler 15 H hosted disk 13 19 28 30 42 46 48 51 55 113 l iconv_open initialize codeset conversion 21 iconv convert UTF 8 to and from UTF 16 21 VMware Inc incremental backup 40 113 incremental restore 80 installation on Linux 16 installation on Windows 16 internationalization i18n 21 L lazy zeroed thick dis
206. w Virtual Machine Download State Create Snapshot Remove Snapshot Configuration Disk Lease Create a Temporary Snapshot on the Target Virtual Machine The low level procedure for creating a snapshot of a virtual machine is documented in the section Creating a Snapshot on page 69 Set the quiesce flag True to make the file system quiescent otherwise the snapshot might represent a transitional system state with inconsistent data Restoring such data might be destructive VMware Inc Designing vSphere Backup Solutions Another flag named memory allows you to include in the snapshot a dump of the powered on virtual machine s in memory state This is not needed for backup so set this flag to False Changed Block Tracking This feature first available in vSphere 4 provides the foundation for incremental or differential backup of virtual disks Your application can back up only changed data as indicated by the QueryChangedDiskAreas method Virtual machines with virtual hardware version 7 and later support changed block tracking These virtual machines contain changeTrackingSupported in the capability field of the VirtualMachine managed object See Changed Block Tracking on Virtual Disks on page 70 for details Extract Backup Data from the Target Virtual Machine Associated with the snapshot you just created are versions of the virtual disks To identify these disks you obtain a moRef to the snapshot you jus
207. ws systems used C Windows Temp Windows XP and Server 2003 use C Documents and Settings lt user gt Local Settings Temp vmware lt user gt Vista Windows 7 and Server 2008 use C Users lt user gt AppData Local Temp vmware lt user gt On all versions of Windows the user s TEMP environment setting overrides the default Temp folder location Temporary is something of a misnomer because files are never deleted from the Temp folder unless the user or an application deletes them If the TEMP or Windows default Temp folder is not found VDDK and other VMware software have a fallback to lt LocalAppDir gt Temp Alternatively your software can set a custom temporary directory as shown in Example 4 1 List Available Transport Methods The VixDiskLib_ListTransportModes function returns the currently supported transport methods as a colon separated string value currently file san hotadd nbd where nbd indicates LAN transport When available SSL encrypted NBD transport is shown as nbdss1 printfC Transport methods s n VixDiskLib_ListTransportModes The default transport priority over the network is san hotadd nbdss1 nbd assuming all are available Connect to VMware vSphere VixDiskLib_ConnectEx connects the library to managed disk on a remote ESX ESXi host or through VMware vCenter Server For hosted disk on the local system it works the same as VixDiskLib_Connect VixDiskLib_ConnectEx takes three additional p
208. www vmware com support developer vc sdk VMware Inc 55 Virtual Disk Programming Guide 56 The Developer s Setup Guide for the VMware vSphere WS SDK has a chapter describing how to set up your programming environment for Microsoft C or Java Some of the information applies to C also The Programming Guide for the vSphere SDK contains some sample code written in Microsoft C but most examples are written in Java and based on the JAX WS development framework ESX ESXi hosts and the VMware vSphere WS API use a programming model based on Web services in which clients generate Web services description language WSDL requests that pass over the network as XML messages encapsulated in simple object access protocol SOAP On ESX ESXi hosts or vCenter Server the vSphere layer answers client requests usually passing back SOAP responses This is a different programming model than the object oriented function call interface of C and the VIX API Virus Scan All Managed Disk Suppose you want to run the antivirus software presented in Scan VMDK for Virus Signatures on page 49 for all virtual machines hosted on an ESX ESXi host Here is the high level algorithm for a VMware vSphere solution that can scan managed disk on all virtual machines To virus scan managed virtual disk 1 Using the VMware vSphere Perl Toolkit write a Perl script that connects to a given ESX ESXi host 2 Call Vim find_entity_views to find the inventory of ev
209. xDiskLib_Grow 28 34 42 VixDiskLib_Init 28 29 35 46 52 55 VixDiskLib_Open 28 30 46 VixDiskLib_Read 28 30 48 49 50 52 VixDiskLib_ReadMetadata 28 31 47 VixDiskLib_Rename 28 34 52 VIXDISKLIB_SECTOR_SIZE 30 49 52 VixDiskLib_Shrink 28 35 VixDiskLib_SpaceNeededForClone 28 31 VixDiskLib_Unlink 28 35 42 52 VixDiskLib_Write 28 30 35 47 51 52 VixDiskLib_WriteMetadata 28 31 47 VixHost_Connect 55 VixHost_Findltems 55 VM configuration information 39 VMDK virtual machine disk file 11 12 19 21 22 31 46 47 49 50 51 52 56 VMFS_FLAT 19 20 51 VMFS_SPARSE 19 VMFS_THIN 19 20 VMware Consolidated Backup VCB 11 VMware vCenter and ESX ESXi 22 VMX specification vmxSpec 29 Volume Snapshot Service VSS 84 VSAN with direct attached storage 24 vSphere APIs for Data Protection VADP 57 WwW walk through of sample program 45 Windows 2008 application consistent quiescing 85 Windows installation 16 Windows On Windows 64 12 VMware Inc
210. y m self signed or m the thumbprint of the target machine s SSL certificate must match the thumbprint provided in the communication configuration structure On Linux SSL certificate verification requires the use of thumbprints there is no mechanism to validate an SSL certificate without a thumbprint On vSphere the thumbprintis a hash obtained from a trusted source such as vCenter Server and passed in the SSLVerifyParam structure from the NFC ticket If you add the following line to the VixDiskLib_InitEx configuration file Linux virtual machines will check the SSL thumbprint vixDiskLib LinuxSSL verifyCertificates 1 The following library functions enforce SSL thumbprint on Linux InitEx PrepareForAccess EndAccess GetNfcTicket and the GetRpcConnection interface that is used by the advanced transports NFC Session Limits NBD employs the VMware network file copy NFC protocol Table 3 4 shows limits on the number of network connections for various host types VixDiskLib_Open uses one connection for every virtual disk that it accesses on an ESX ESXi host VixDiskLib_Clone also requires a connection It is not possible to share a connection across disks These are host limits not per process limits and do not apply to SAN or HotAdd Table 3 4 NFC Session Connection Limits Host Platform When Connecting Limits You To About vSphere 4 to an ESX host 9 connections directly 27 connections through vCenter Server vSph
211. y survive even through to the next power on In nonpersistent mode changes to the virtual disk are discarded when the virtual machine powers off The VMDK files revert to their original state The virtual disk library does not encapsulate this distinction which is a virtual machine setting VMDK File Naming Table 3 1 explains the different types of virtual disk The first column corresponds to Virtual Disk Types on page 19 but without the VIXDISKLIB_DISK prefix The third column gives the possible names of VMDK files as implemented on Workstation and ESX ESXi hosts NOTE When you open a VMDK file with the virtual disk library always open the one that points to the others not the split or flat sectors The file to open is most likely the one with the shortest name For information about other virtual machine files see section Files that Make Up a Virtual Machine in the VMware Workstation User s Manual On ESX ESXi hosts VMDK files are type VMFS_FLAT or VMFS_THIN Table 3 1 VMDK Virtual Disk Files Disk Type in API MONOLITHIC_SPARSE Virtual Disk Creation on VMware Host In Select A Disk Type accepting the defaults by not checking any box produces one VMDK file that can grow larger if more space is needed The lt vmname gt represents the name of a virtual machine On VMFS partitions this is name of the disk descriptor file Filename on Host lt vmname gt vmdk MONOLITHIC_FLAT or VMFS_FLAT or VM
212. y kind of file system on the virtual disks VMware Inc 61 Virtual Disk Programming Guide Doing a Restore Operation The two scenarios of restore operation are described below m Restoring an Existing Virtual Machine to a Previous State on page 62 m Creating a New Virtual Machine on page 63 Prerequisites for Restore To complete a restore the calling process requires the permissions in Table 7 2 Table 7 2 Required permissions to complete a restore Privilege Category Privilege Subcategory Privilege Virtual Machine Inventory Create Remove Configuration Settings Change Resource Resource Assign Virtual Machine to Resource Pool For security reasons programs are not granted write access to the disks of a running virtual machine Before you shut it down you should determine the run state of the virtual machine Run state information is available from the PropertyCol lector and if you keep this information up to date your application already knows the run state of the virtual machine To change the run state you must have the moRef of the virtual machine Use this moRef in a PowerOnVM_Task call through the server connection For virtual machine shutdown call the PowerOffVM_Task method Restoring an Existing Virtual Machine to a Previous State The following steps restore a virtual machine to a certain saved state 1 Shut down the virtual machine if it is not already shut down 2 With SAN advan
213. y reload the base virtual disk using the full backup that started the most recent series of incremental backups 4 Create a snapshot This is mandatory for SAN mode restore 5 For SAN mode restore disable changed block tracking SAN writes are not possible with it enabled 6 Sequentially restore the incremental backup data You can do this either forwards or backwards If you work forwards the restore might write some sectors more than once If you work backwards you must keep track of which sectors were restored so as to avoid restoring them again from older data a From your backup records get the change ID of the incremental backup to be restored Your software must also store the changed block information so it knows which sectors of virtual disk to restore Once you start restoring virtual disk the change tracking mechanism will misreport b Restore only changed areas to the virtual disks referred to by the snapshot This ensures that you do not write the data to the redo log created by the snapshot When restoring a thin provisioned sparse disk use the star change ID to avoid writing zeroes to the unallocated blocks c Repeat Step a and Step b as necessary by applying incremental backup data sets in order 7 If applicable SAN mode revert to the base virtual disk thus eliminating the snapshot Restore Fails with Direct Connection to ESXi Host Sometimes you must restore a virtual machine directly to an ESXi host for exampl
214. y then call the function CheckForUpdates which on the first try when it must contain an empty string for the version number returns a complete dump of all the requested properties from all the eligible objects along with a version number Subsequent calls to CheckForUpdates must contain this version number to indicate to the PropertyCollector that you seek any changes that deviate from this version The result is either a partial list containing only the changes from the previous version including a new version number or a return code indicating no data has changed The following code sample shows how to check for updates String updateVersion Start with no version UpdateSet changeData serviceConnection CheckForUpdates pcRef updateVersion if changeData nil updateVersion changeData getVersion Extract the version of the data set Ife ee Get changes since the last version was sent UpdateSet latestData serviceConnection CheckForUpdates pcRef updateVersion If instead you wish to wait for updates to occur you must create a task thread that blocks on the call WaitForUpdates This task thread would return changes only as they occur and not at any other time However if the request times out you must renew it NOTE The order of property retrieval is not guaranteed Multiple update requests may be needed VMware Inc 67 Virtual Disk Programming Guide 68 Extracting Information from the Change Data
215. ype of the entity it is referring to Example 8 16 Using the SDK for NET To Access MoRefs using com vmware vcloud sdk using com vmware vcLloud api rest schema Log in with admin privileges and get admin view of vDC containing the vApp VApp vapp VApp utility class from vCloud SDK Identify vApp List lt VM gt Vms Get list of children VM s Vms vapp GetChildrenVms foreach VM vm in Vms Console WriteLine Access vSphere information for VM M Info from vSphere VimObjectRefType vmRef vm GetVMVimRef Console WriteLine VirtualMachine vmRef moRefField Datastore Info from vSphere for VM VimObjectRefType datastoreRef vm GetVMDatastoreVimRef Console WriteLine Datastore datastoreRef moRefField Host info form vSphere for VM VimObjectRefType hostRef vm GetVMHostVimRef Console WriteLine Host hostRef moRefField Restoring vApps During the restore process the backup software typically restores a virtual machine in vSphere using the virtual machine configuration and disk files In situations where the vApp has been lost from the vCloud Director inventory the backup software needs to first restore the virtual machine in vSphere and then import the virtual machine into vCloud Director VMware Inc 101 Virtual Disk Programming Guide Although the vApp may contain multiple virtual machines in the view of vCloud Director the virtual

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