Invoke-Command with ScriptBlock Works on Local Server - Remotely Resultset is Empty

Question

When trying to obtain the Citrix XenApp 6.5 server status by using the following code, a resultset is returned when run in PowerShell locally on a Zone Data Collector:

$serverName = "SOMECITRIXSERVER"
$Invoke-Command -ScriptBlock {Add-PSSnapin Citrix.XenApp.Commands}
$serverStatus = Get-XAServer | select ServerName,@{n="InMaintenanceMode";e={ if($_.LogOnMode -like "Prohibit*"){$true}elseif($_.LogOnMode -eq "AllowLogons"){$false} }} | where {$_.ServerName -eq $serverName} | Select InMaintenanceMode}
Write-Output "Status: $serverStatus.InMaintenanceMode"
Status: false

The same scriptblock is then executed in PowerShell with computername set to a ZDC and credentials supplied. No exceptions are thrown and the resultset is empty:

$zoneDataCollector = "SOMEZDCHOST"
$serverName = "SOMECITRIXSERVER"
$key = (somekeyvaluehere)
$passwordZDC = cat CredentialFile.txt | convertto-securestring -key $key
$credZDC = new-object -typename System.Management.Automation.PSCredential -argumentlist $usernameZDC, $passwordZDC
$ZDCSession = New-PSSession -ComputerName $zoneDataCollector -Credential $credZDC
$Invoke-Command -Session $ZDCSession -ScriptBlock {Add-PSSnapin Citrix.XenApp.Commands}
$serverStatus = Invoke-Command -Session $ZDCSession -ScriptBlock {Get-XAServer | select ServerName,@{n="InMaintenanceMode";e={ if($_.LogOnMode -like "Prohibit*"){$true}elseif($_.LogOnMode -eq "AllowLogons"){$false} }} | where {$_.ServerName -eq $serverName} | Select InMaintenanceMode}
Write-Output "Status: $serverStatus.InMaintenanceMode"
Status: 

Running a Wireshark network packet capture is not very helpful because the WinRM traffic payload is encrypted.

Any ideas as to why the command within the scriptblock would work locally, but return an empty resultset without throwing exceptions?

Thanks! ds

Answer 1

When you using the invoke-command on a remote server, and you need to call a variable from the local machine, then you need to add params to the scriptblock and argumentslist

So your code should look like

$serverStatus = Invoke-Command -Session $ZDCSession -ScriptBlock {param($serverName) Get-XAServer | select ServerName,@{n="InMaintenanceMode";e={ if($_.LogOnMode -like "Prohibit*"){$true}elseif($_.LogOnMode -eq "AllowLogons"){$false} }} | where {$_.ServerName -eq $serverName} | Select InMaintenanceMode} –argumentlist $serverName