Invoke-Command and ShellId Issues

Question

Hi all,
I'm struggling to figure out what is going on here.
I'm trying to add a domain user to a VM's local administrators group via this:
$localAdminBlock = `
$objUser = [ADSI]("WinNT://domain/domainaccount")
$objGroup = [ADSI]("WinNT://$vm/Administrators")
$objGroup.PSBase.Invoke("Add",$objUser.PSBase.Path)
Invoke-Command -ComputerName $vm -Scriptblock $localAdminBlock -Credential $adminCreds
I receive an error:
"Processing data from remote server TestServer failed with the following error message: The request for the Windows Remote Shell with ShellId <id here> failed because the shell was not found on the server.  Possible causes are: the specified
ShellId is incorrect or the shell no longer exists on the server.  Provide the correct ShellId or create a new shell and retry the operation..."
Any idea what's going on?
Thanks.

Answer 1

You need to use $using:vm instead of $vm since you are passing a value from a local variable into the scriptblock which
is executed remotely. If you don't do this then the $vm will be $null in the remote session. If you use $using:vm then Invoke-Command will evaluate the local $vm variable and use this value in the remote session.
$localAdminBlock = `
$objUser = [ADSI]("WinNT://domain/domainaccount")
$objGroup = [ADSI]("WinNT://$using:vm/Administrators")
$objGroup.PSBase.Invoke("Add",$objUser.PSBase.Path)
Invoke-Command -ComputerName $vm -Scriptblock $localAdminBlock -Credential $adminCreds
--Neptune
That was the issue, thanks a lot!