PowerShell Script for Exporting a virtual machine

I need to automate the process of exporting a virtual machine recently – and when I checked around I found that while there are a number of sample scripts out there that show you how to do this (some even on this blog) they are all written in VBScript.  As I am now to the stage where PowerShell is my preferred scripting language – I sat down and wrote up this short script:

 # Function for handling WMI jobs / return values
 Function ProcessResult($result, $successString, $failureString)
 {
    #Return success if the return value is "0"
    if ($result.ReturnValue -eq 0)
       {write-host $successString} 
  
    #If the return value is not "0" or "4096" then the operation failed
    ElseIf ($result.ReturnValue -ne 4096)
       {write-host $failureString " Error value:" $result.ReturnValue}
  
    Else
       {#Get the job object
       $job=[WMI]$result.job
  
       #Provide updates if the jobstate is "3" (starting) or "4" (running)
       while ($job.JobState -eq 3 -or $job.JobState -eq 4)
          {write-host $job.PercentComplete "% complete"
           start-sleep 1
  
           #Refresh the job object
           $job=[WMI]$result.job}
  
        #A jobstate of "7" means success
        if ($job.JobState -eq 7)
           {write-host $successString
           return $true}
        Else
           {write-host $failureString
           write-host "ErrorCode:" $job.ErrorCode
           write-host "ErrorDescription" $job.ErrorDescription
           return $false}
        }
 }
  
 # Prompt for the Hyper-V Server to use
 $HyperVServer = Read-Host "Specify the Hyper-V Server to use (enter '.' for the local computer)"
  
 # Prompt for the virtual machine to use
 $VMName = Read-Host "Specify the name of the virtual machine"
  
 # Prompt for the path to export to
 $ExportPath = Read-Host "Specify the path to place the exported virtual in"
  
 # Get the management service
 $VMMS = gwmi -namespace root\virtualization Msvm_VirtualSystemManagementService -computername $HyperVServer
  
 # Get the virtual machine object
 $VM = gwmi MSVM_ComputerSystem -filter "ElementName='$VMName'" -namespace "root\virtualization" -computername $HyperVServer
  
 # Export the virtual machine
 $result = $VMMS.ExportVirtualSystem($VM, $true, $ExportPath)
  
 # Check to make sure we succeeded
 $exportSucceeded = ProcessResult $result "Virtual machine exported." "Failed to export virtual machine."

Some quick notes to make about this script:

• This script takes a Hyper-V server name, a virtual machine name and an export path – and then performs a full export to the requested location.
• I am using the older (deprecated) ExportVirtualSystem method here – and not ExportVirtualSystemEx (which I really should do).  The main reason for this is that while ExportVirtualSystemEx is a lot more powerful than ExportVirtualSystem, ExportVirtualSystem works perfectly fine for this basic use case and is much easier to script.

Cheers,
Ben

simpleExport.zip