Start services in parallel

Question

I have a script which checks if certain service on different servers is up, if it is not, the script should start the service.

The problem is, it doesn't start the services in parallel, instead it waits until each service is started.

Code:

$server_list = Get-Content -path D:\Path\list_of_servers.txt

$server_list | foreach { 
 (Get-Service -Name '*Service Name*' -computername $_) | Where-Object {$_.status -eq "Stopped"} | Set-Service -Status Running
}

I know it's due to the way the script is written, but maybe some of you have any suggestions how to make it better?

Cheers!

Answer 1

Here is an example of parallel processing using Powershell and Workflows:

$server_list = Get-Content -path D:\Path\list_of_servers.txt
workflow MyWorkflow
{
    foreach -parallel($s in $server_list) { 
        inlinescript { (Get-Service -Name '*Service Name*' -PSComputerName $s) | Where-Object {$_.status -eq "Stopped"} | Set-Service -Status Running
        }
    }
}

Using Powershell V2 and jobs

Untested code, but should be close:

$server_list = Get-Content -path D:\Path\list_of_servers.txt

$maxJobs = 5
$scriptblock = { 
(Get-Service -Name $args[1] -ComputerName $args[0]) | Where-Object {$_.status -eq "Stopped"} | Set-Service -Status Running
}

foreach ($s in $server_list)
{
    $arguments = @($s, $service)

    $running = @(Get-Job | Where-Object { $_.State -eq 'Running' })
    while ($running.Count -gt ($maxJobs -1)) {
        $done = Get-Job | Wait-Job -Any
        $running = @(Get-Job | ? {$_.State -eq 'Running'})
    }   
    start-job -scriptblock $scriptblock -ArgumentList $arguments
}
Get-Job | Wait-Job
Get-Job | Receive-Job