Assistance with Invoke-Command ScriptBlock error.

[daviperry79 Participant Topics: 2 Replies: 2 Points: 21Rank: Member]

Hello All,
What I am trying to accomplish is for this script to take a list of remote servers and find the “Service Name” of a service, and then convert that into a PID that will be used later for process termination. This is only a snippet of a script that will take a list of servers, ask the user for the “Service Name” of a service and kill that task. For a single server, I have it working.
Here is the issue, the script below is as far as I gotten toward my goal with a list of servers. This particular version seems the best, but gives an error “Get-Process: Cannot find a process withthe name “whatever”. I have verified the process exists with the name provided. In fact, the process that I am testing with has the same name as the Service Name except the process has ‘exe’ appended. Didn’t matter however.
It appears that Invoke-Command has trouble with multiple commands in the ScriptBlock, but I don’t know another way to make this happen.
I am limited to PoSH 5.1 and Get-Process and Get-WMIObject can’t accept the $server variable in the -ComputerName parameter of Invoke-Command. They only work if thier -ComputerName parameter is used.
Any assistance would be appreciated.

PowerShell

$ServerList = 'server01','server02' $SvcName = 'whatever' $ted = ForEach ($Server in $ServerList){ Invoke-Command -ScriptBlock { $ProcID = Invoke-Command -ScriptBlock {(Get-Process -ComputerName $server -name $SvcName).Id}; $ProcObj = Invoke-command -ScriptBlock {Get-WmiObject Win32_Process -ComputerName $server | ?{ $_.ProcessId -match $ProcID }} } }

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$ServerList = 'server01','server02' $SvcName = 'whatever'    $ted = ForEach ($Server in $ServerList){     Invoke-Command -ScriptBlock {           $ProcID = Invoke-Command -ScriptBlock {(Get-Process -ComputerName $server -name $SvcName).Id};           $ProcObj = Invoke-command -ScriptBlock {Get-WmiObject Win32_Process -ComputerName $server  | ?{ $_.ProcessId -match $ProcID }}         } }

[Mike R.]

Variables defined outside of the Invoke-Command script block cannot be referenced inside the Invoke-Command script block.  So in your case line 7, $SvcName does not exist ($null).  To “fix” this you would need to preface $using: or pass the object in as an argument to a parameter.  Either way I would change the approach.  Based on what your requirements are per the post here’s what I would do:

PowerShell

$ServerList = 'server01','server02' $ted = Invoke-Command -ComputerName $ServerList -ScriptBlock { $SvcName = 'whatever' $PID = Get-CimInstance -ClassName win32_service | Where-Object {$_.Name -eq $SvcName} | Select-Object -ExpandProperty ProcessID #Do whatever you want to the process here. Just reference $PID for the pid } #invoke-command script block

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$ServerList = 'server01','server02'   $ted = Invoke-Command -ComputerName $ServerList -ScriptBlock {     $SvcName = 'whatever'     $PID = Get-CimInstance -ClassName win32_service |         Where-Object {$_.Name -eq $SvcName} |             Select-Object -ExpandProperty ProcessID     #Do whatever you want to the process here. Just reference $PID for the pid        } #invoke-command script block

Note the computername parameter of invoke-command will take an array so no need for the foreach loop.  Any objects returned from the remote script block will be assigned to $ted with a new property of PSComputerName that will tell you which server it came from.

• This reply was modified 1 month, 1 week ago by Mike R..

[Rob Simmers Participant Topics: 17 Replies: 1951 Points: 3,987Rank: Community Hero]

There are numerous issues. This is invoking a command locally, to invoke a command locally again to make a remote call from the local server to the remote server. WMI and Get-Process (which in the background is using WMI) can make RPC calls to the server with DCOM:

PowerShell

$ServerList = 'server01','server02' $SvcName = 'whatever' $ted = ForEach ($Server in $ServerList){ $ProcID = (Get-Process -ComputerName $server -name $SvcName).Id $ProcObj = Get-WmiObject Win32_Process -ComputerName $server | ?{ $_.ProcessId -match $ProcID } }

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$ServerList = 'server01','server02' $SvcName = 'whatever'    $ted = ForEach ($Server in $ServerList){     $ProcID = (Get-Process -ComputerName $server -name $SvcName).Id     $ProcObj = Get-WmiObject Win32_Process -ComputerName $server  | ?{ $_.ProcessId -match $ProcID } }

If you want to use PS Remoting with WSMAN, then you can do it like this to execute the commands remotely on the server. To pass a local variable to the remote session, you need to use the ‘Using:’ keyword:

PowerShell

$ServerList = 'server01','server02' $SvcName = 'whatever' $ted = ForEach ($Server in $ServerList){ Invoke-Command -ComputerName $server -ScriptBlock { $ProcID = (Get-Process -name $using:SvcName).Id $ProcObj = Get-WmiObject Win32_Process | ?{ $_.ProcessId -match $ProcID } } }

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$ServerList = 'server01','server02' $SvcName = 'whatever'    $ted = ForEach ($Server in $ServerList){     Invoke-Command -ComputerName $server -ScriptBlock {           $ProcID  = (Get-Process -name $using:SvcName).Id           $ProcObj = Get-WmiObject Win32_Process  | ?{ $_.ProcessId -match $ProcID }         } }

Also, keep in mind that this is assuming there is 1 returned value. Using -match is a regex, a better comparison would be using -eq (equals) for a straight comparison.

[daviperry79 Participant Topics: 2 Replies: 2 Points: 21Rank: Member]

Yea, I had a feeling that I was on a bad path with this one, but couldn’t sort out exactly what. Thank you for the guidance.

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