Remote variable

Question

I am having an issue with passing variables to a remote powershell session and I've searched everywhere on the internet I can think of so I'm hoping someone out there can help. I have a function calling a job which is telling it to start a scriptblock

What I'm trying to do is write a script to allow me to failover clusters from one VM. It works fine if everything is hardcoded but that means I have to change the script for every failover and that just won't save me anytime at all.

$Computer = Server1
$Clustergrp = Cluster1


function FAILOVER(){
$job = Start-Job -scriptblock $JobScript
do {[System.Windows.Form.Application]::DoEvent() } until ($Job.State -eq "Completed")


$JobScript = 
{
Invoke-Command -ComputerName $using:Computer -ScriptBlock {Move-ClusterGroup -Name $using:Clustergrp}
}

What am I missing here? Help please!

I've tried using arguments and $using:variable but nothing seems to work. Yet if I hardcode everything in the scriptblock it works everytime.

I've also tried just using -ComputerName $Computer -ScriptBlock{.....} but that didn't work either.

Answer 1

General points:

• Invoke-Command has an -AsJob parameter, so there's no need for creating a job with Start-Job first.

• To wait for a job's completion, use the Wait-Job cmdlet.

• If you want to wait right away, i.e. if you want synchronous execution to begin with, simply omit -AsJob.

  • Note that Invoke-Command's -ComputerName parameter accepts an array of computer names that are then targeted in parallel.

---

As for what you tried:

You're nesting two out-of-runspace (out-of-process) scopes, which also requires nesting the use of the $using: scope:

$Computer = 'Server1'
$Clustergrp = 'Cluster1'

$JobScript = {
  # Create a *local* variable from the caller's
  # $Clustergrp value, so it can again be referenced with
  # $using: in the remotely executing Invoke-Command script block.
  $Clustergrp = $using:Clustergrp
  Invoke-Command -ComputerName $using:Computer -ScriptBlock { 
    Move-ClusterGroup -Name $using:Clustergrp
  }
}

function FAILOVER {
  $job = Start-Job -ScriptBlock $JobScript
  $job | Wait-Job
}

Answer 2

Invoke-Command -ComputerName $using:Computer -ArgumentList $arg1 -ScriptBlock {param($arg) Move-ClusterGroup -Name $arg[0]}