CODEWITHSUNDEEP
powershellpowercli
r4d1um
r4d1um

Reputation: 548

Hardening PowerShell Script for Automating Usage of VMs using PowerCLI

To get a clean environment to run some other scripts I need to revert a Virtual Machine on an ESX Host every time when a Scheduled Task triggers it.

Reverting can be achieved by running:

Set-VM -VM $VMName -Snapshot "MySnapshot" -Confirm:$false

Starting can be achieved by running:

Start-VM -VM $VMName

Stopping can be achieved by running:

Shutdown-VMGuest -VM $VMName -Confirm:$false

How can I handle this in a more secure way, e.g to be able to handle Errors when reverting, starting or stopping the VM and get a return if one of these Tasks were being executed successfully?

I am using PowerCLI 6.5.0.

Upvotes: 1

Views: 591

Answers (1)

Timothée Christin
Timothée Christin

Reputation: 63

You can use several methods to achieve this. Here are 2 examples :

  1. Using -ErrorVariable

    # Revert VM
Set-VM -VM $VMName -Snapshot "MySnapshot" -Confirm:$false -ErrorVariable revertError

If ($revertError)
{
    Write-Host "An error occured while reverting snapshot !" -ForegroundColor Red
    Write-Host $revertError
}
Else
{
    Write-Host "Successfully reverted to snapshot." -ForegroundColor Green
}

# Start VM
Start-VM -VM $VMName -ErrorVariable startError

If ($startError)
{
    Write-Host "An error occured while starting VM :" -ForegroundColor Red
    Write-Host $startError
}
Else
{
    Write-Host "Successfully started VM." -ForegroundColor Green
}

# Stop VM
Shutdown-VMGuest -VM $VMName -Confirm:$false -ErrorVariable shutdownError

If ($shutdownError)
{
    Write-Host "An error occured while shutting down guest OS of VM :" -ForegroundColor Red
    Write-Host $shutdownError
}
Else
{
    Write-Host "Successfully stopped VM." -ForegroundColor Green
}

  2. Using Try/Catch as mentionned by @mark-wragg

    # Revert VM
Try
{
    # Temporarily make all errors terminating
    $errorActionPreference = "Stop"
    Set-VM -VM $VMName -Snapshot "MySnapshot" -Confirm:$false
    Write-Host "Successfully reverted to snapshot." -ForegroundColor Green
}
Catch
{
    Write-Host "An error occured while reverting snapshot !" -ForegroundColor Red
    Write-Host $_.Exception.Message
}
Finally
{
    $errorActionPreference = "Continue"
}

# Start VM
Try
{
    # Temporarily make all errors terminating
    $errorActionPreference = "Stop"
    Start-VM -VM $VMName
    Write-Host "Successfully started VM." -ForegroundColor Green
}
Catch
{
    Write-Host "An error occured while starting VM :" -ForegroundColor Red
    Write-Host $_.Exception.Message
}
Finally
{
    $errorActionPreference = "Continue"
}

# Stop VM
Try
{
    # Temporarily make all errors terminating
    $errorActionPreference = "Stop"
    Shutdown-VMGuest -VM $VMName -Confirm:$false
    Write-Host "Successfully stopped VM." -ForegroundColor Green
}
Catch
{
    Write-Host "An error occured while shutting down guest OS of VM :" -ForegroundColor Red
    Write-Host $_.Exception.Message
}
Finally
{
    $errorActionPreference = "Continue"
}

Upvotes: 1

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