Waiting for a VM to come back

In my previous post, I wrote about upgrading vCPU's, and that I want to do several other things as well. If you upgrade a vCPU on a VM, it could very well be that the Windows guest wants a second reboot. I've found that simply rebooting and waiting for a while is inefficient. So I usually check if the VMware tools are back online.

I've made that into a function, to exactly that:

function WaitforVM($VM)

{

    while (((get-vm $VM ).ExtensionData.Guest.ToolsRunningStatus ) -ne "guestToolsRunning" )

        {

            Write-Host "Waiting for machine to come back....." -ForegroundColor Yellow

            Sleep 5

        }

}

Now all you have to do, is to start the VM after the CPU addition, wait, then restart and wait again:

Start-VM -VM $VM -Confirm:$False

WaitforVM -VM $VM

Restart-VMGuest -VM $VM -Confirm:$False

WaitforVM -VM $VM

Nice, right? Obviously this function can be used for other things, like being used in scripts when you create a new VM from template and boot it up to see if that VM is live already.