Wednesday, June 18, 2008

Hyper-V WMI – Cloning Virtual Machines Using Import/Export

Here’s a quick tour of the script…

This script takes 4 parameters:

  • MasterVM – this is the name of the VM that will be cloned
  • Path – this is the base path where the clones will reside
  • NewName – this is what the cloned VM’s will be named
  • HyperVHost – this is the name of the host that the script will execute against

The function ProcessWMIJob takes the return of a WMI method call and then processes the job waiting for the job to complete and throwing an exception if the job failed.

The main part of the script retrieves the Msvm_VirtualSystemManagmentService class and the MasterVM’s Msvm_ComputerSystem. It then loops 10 times, first changing the name of the VM and then exporting the VM and finally re-importing the VM. After it completes the 10 interactions it restores the name of original name of the MasterVM.

param
(
[
string]$MasterVM = $(Throw "MasterVM required"),
[
string]$Path = $(Throw "Path required"),
[
string]$NewName = "VMCopy",
[
string]$HyperVHost = "localhost"
)


function ProcessWMIJob
{
param
(
[
System.Management.ManagementBaseObject]$Result
)

if ($Result.ReturnValue -eq 4096)
{
$Job = [WMI]$Result.Job

while ($Job.JobState -eq 4)
{
Write-Progress -Id 2 -ParentId 1 $Job.Caption -Status "Executing" -PercentComplete $Job.PercentComplete
Start-Sleep 1
$Job.PSBase.Get()
}
if ($Job.JobState -ne 7)
{
Write-Error $Job.ErrorDescription
Throw $Job.ErrorDescription
}
}
elseif ($Result.ReturnValue -ne 0)
{
Throw $Result.ReturnValue
}
Write-Progress $Job.Caption -Status "Completed" -PercentComplete 100 -Id 2 -ParentId 1
}

#Main Script Body
$VMManagementService = Get-WmiObject -Namespace root\virtualization -Class Msvm_VirtualSystemManagementService -ComputerName $HyperVHost
$SourceVm = Get-WmiObject -Namespace root\virtualization -Query "Select * From Msvm_ComputerSystem Where ElementName='$MasterVM'" -ComputerName $HyperVHost
$a = 0


while ($a -lt 10) {
write-progress -Id 1 "Cloning Vm's" -Status "Executing" -percentcomplete (($a / 10)*100)
$tempVMName = "$NewName - $a"
$VMSettingData = Get-WmiObject -Namespace root\virtualization -Query "Associators of {$SourceVm} Where ResultClass=Msvm_VirtualSystemSettingData AssocClass=Msvm_SettingsDefineState" -ComputerName $HyperVHost
$VMSettingData.ElementName = $tempVMName

$Result = $VMManagementService.ModifyVirtualSystem($SourceVm, $VMSettingData.PSBase.GetText(1))
ProcessWMIJob $Result

$Result = $VMManagementService.ExportVirtualSystem($SourceVm, $TRUE, "$Path")
ProcessWMIJob $Result

$Result = $VMManagementService.ImportVirtualSystem("$Path\$tempVMName", $TRUE)
ProcessWMIJob $Result

$a ++
}


write-progress -Id 1 -Completed $TRUE -Activity "Cloning Vm's"
$VMSettingData = Get-WmiObject -Namespace root\virtualization -Query "Associators of {$SourceVm} Where ResultClass=Msvm_VirtualSystemSettingData AssocClass=Msvm_SettingsDefineState" -ComputerName $HyperVHost
$VMSettingData.ElementName = $MasterVM

$Result = $VMManagementService.ModifyVirtualSystem($SourceVm, $VMSettingData.PSBase.GetText(1))
ProcessWMIJob $Result

Source: Taylor Brown
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