Howto manually add a VM Configuration to Hyper-V
With Hyper-V you cannot simply „Add“ a configuration file to your Hyper-V machine as you could with Virtual Server. Mainly because of the use of Live Snapshots. The recommended way is to use Export and Import.
If you have a given VHD it is way easier to create a new VM and simply add the VHD to it. If you used snapshots, see my earlier blog on how to merge them to a new VHD.
However, recently my colleague Walter Weinfurter had a customer issue, where we only had the flat directory structure and needed to restore that. Here’s how we managed to get this running:
We start from a folder that contains the VM in v:\manualrecover
.
In this folder you usually have:
1. The machine VHD
2. The Virtual Machines Folder with
a: The <GUID>.xml File holding the machine Configuration
b: The <GUID> Folder
3. The Snapshots Folder with a <Snapshot GUID>.xml
Hyper-V uses a new Feature in Windows 2008 called Service SIDs. To access files from a VM, these files need to give this Service SID access permissions.
This SID is a combination of the Service SID ""NT VIRTUAL MACHINE" and the VM GUID
Example:
"NT VIRTUAL MACHINE\2F855D88-F990-47BA-95D6-0029BCD8C059"
Note, The GUIDS we used here are from our VM, You will need to adjust to the GUIDs used on your installation
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The first step to make this machine known to Hyper-V is to create a Symbolic link to the <GUID>.xml configuration files, in the following folder:
"%systemdrive%\programdata\Microsoft\Windows\Hyper-V\Virtual Machines"
We use the mklink command built into cmd.exe
C:\>mklink "%systemdrive%\programdata\Microsoft\Windows\Hyper-V\Virtual Machines\2F855D88-F990-47BA-95D6-0029BCD8C059.xml" "V:\manualrecover\Virtual Machines\2F855D88-F990-47BA-95D6-0029BCD8C059.xml"
The VM Name should now already appear in Hyper-V Manager
We need to add the Service SID to this Symbolic link so that Hyper-V is allowed to access it
C:\>icacls "%systemdrive%\programdata\Microsoft\Windows\Hyper-V\Virtual Machines\2F855D88-F990-47BA-95D6-0029BCD8C059.xml" /grant "NT VIRTUAL MACHINE\2F855D88-F990-47BA-95D6-0029BCD8C059":(F) /L
Note the /L parameter to indicate we work on a symbolic link
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We also need to give the Service SID access to all files of our VM
C:\>icacls v:\manualrecover\ /T /grant "NT VIRTUAL MACHINE\2F855D88-F990-47BA-95D6-0029BCD8C059":(F)
Note for simplicity we give Full Control, whereas the default is more granular
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If your machine had Snapshots, we also need to create another symbolic link
The snapshot itself has yet another guid.xml found in the snapshots folder.
C:\>mklink "%systemdrive%\ProgramData\Microsoft\Windows\Hyper-V\Snapshots\7DD74401-C2B4-4BD9-8079-3D48D8A78B32.xml" "V:\manualrecover\Snapshots\7DD74401-C2B4-4BD9-8079-3D48D8A78B32.xml"
Also give the Service SID access here too:
C:\>icacls "%systemdrive%\ProgramData\Microsoft\Windows\Hyper-V\Snapshots\7DD74401-C2B4-4BD9-8079-3D48D8A78B32.xml" /grant "NT VIRTUAL MACHINE\2F855D88-F990-47BA-95D6-0029BCD8C059":(F) /L
You will need to do the above for each individual snapshot!
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Before starting the VM, open the settings of the VM and assign the Network Adapters to the correct Switches, as those need to be created newly on the switch.
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NOTE:
This is not a supported way of adding a VM to Hyper-V. Use this just for disaster recovery, and once you are able to run the VM, backup your VM and recreate it from scratch.
If you restore to a different drive/ or folder, you may need to manually adjust the path to the VHD, and Snapshots make this far more complicated .
NOTE2: This procedure does not work on Windows Server 2008 R2.
Cheers
Robert
