Azure Automation: New-CSOnlineSession MaxShell Issue

3 minute read

Description:

So I had my first issue with Azure Automation the other day that I had to open a support case for. I was using a script that connect to Skype Online and the session would just hang for 5 minutes when ran from Azure Automation but worked fine when ran locally on the hybrid worker. The offending code:

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   Write-Output "Connecting to SkypeOnline Server..."
   $vroPass = Get-Pass
   $userName = 'someAccount@domain.com'
   $pw = ConvertTo-SecureString -String $vroPass -AsPlainText -Force
   $cred = New-Object -Typename System.Management.Automation.PSCredential -Argumentlist $username, $pw
   $session = New-CsOnlineSession -Credential $cred

   Import-PSSession $session
   Write-Output "Connecting to SkypeOnline Server...Completed"

The issue: It would hang for 5 minutes and then error with the MaxShell error I had seen before:

To Resolve:

  1. Obviously I ran the commands in that post to try and fix but that didn’t work.

  2. So I tried a more detailed approach:

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    enable-psremoting -force 
cd WSMan:\localhost\Shell 
set-item MaxConcurrentUsers 100 
set-item MaxProcessesPerShell 10000 
set-item MaxMemoryPerShellMB 1024 
set-item MaxShellsPerUser 1000 
cd WSMan:\localhost\Plugin\microsoft.powershell\Quotas 
set-item MaxConcurrentUsers 100 
set-item MaxProcessesPerShell 10000 
set-item MaxShells 1000 
set-item MaxShellsPerUser 1000 
restart-service winrm

  3. So after establishing that it works locally on the machine, the next thing I tried was having the hybrid worker try and launch the script:

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    Write-Output "Launching script..."
Set-Location "S:\sched-tasks\phone-numbers"
$ScriptFile = 'S:\sched-tasks\phone-numbers\connect.ps1'
$Start = @{ 
'FilePath'         = 'powershell.exe'
'NoNewWindow'      = $true
'WorkingDirectory' = 'S:\sched-tasks\phone-numbers'
'ArgumentList'     = @( '-f', $ScriptFile,
   '-ExecutionPolicy', 'Bypass',
   '-NoProfile'
)
}
Start-Process @Start -Wait
#Start-Process -FilePath ".\connect.ps1" -Wait
Write-Output "Launching script...Completed"
    • But all this would do is start another Orchestrator.Sandbox.exe just like the hybrid workers use to run runbooks.

  4. Next I tried creating a scheduled task and have the runbook run the scheduled task. It would then wait for powershell.exe to exit for it to know that it completed:

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    Write-Output "Starting scheduled task..."
Start-ScheduledTask -TaskName 'Start-PhoneNumbers'
Write-Output "Starting scheduled task...Completed"

Start-Sleep -Seconds 5

$p = Get-Process -Name "powershell"

If ( $($p.count) -gt 0)
{
Write-Output "Scheduled task launched successfully"
Write-Output "Checking if completed..."
do
{
   Try
   {
      $p = Get-Process -Name "powershell" -ErrorAction "Stop"  #| Where-Object { $_.id -ne $pid } - This doesn't work because process is Orchestrator.Sandbox.exe
      #write-output "count: $($p.count)"
   }
   Catch
   {
      continue
   }
   
   Start-Sleep -Seconds 1

} until ( $($p.count) -eq 0)

Write-Output "Checking if completed...Completed"

}
Else
{
Write-Output "Scheduled task did not launch successfully"
Write-Error "Terminating runbook"
}
    • This seemed to work as the task would run and powershell would exit, but it never returned back to the runbook that it was completed for some reason.

  5. The one that ended up working was to monitor the last write time of a file that the script creates and, if it less than five minutes old, exit successfully.

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    Write-Output "Starting scheduled task..."
Start-ScheduledTask -TaskName 'Start-PhoneNumbers'
Write-Output "Starting scheduled task...Completed"

Start-Sleep -Seconds 5

$file = Get-Item "S:\sched-tasks\phone-numbers\numbers.csv"
$written = $($file.Lastwritetime)
$time = New-TimeSpan -Start $written -End (Get-Date)
If ( $($time.minutes) -lt 5 )
{
Write-Output "Scheduled task did not launch successfully"
Write-Error "Terminating runbook"
}
Else
{
Write-Output "Scheduled task launched successfully"
Write-Output "Checking if completed..."
do
{
   $file = Get-Item "T:\sched-tasks\phone-numbers\numbers.csv"
   $written = $($file.Lastwritetime)
   $time = New-TimeSpan -Start $written -End (Get-Date)
   Start-Sleep -Seconds 1
   #write-output "time: $($time.minutes)"
} until ( $($time.minutes) -lt 5)
Write-Output "Checking if completed...Completed"
}

Write-Output "Runbook completed"

  6. Couple notes:

    • This works because the script is launched every 2 hours so if the CSV is less than 5 minutes old there is a problem.
    • The support request was closed because they were unable to determine what to do as of now
    • I feel in a later version of Azure Automation that running powershell runbooks and not workflows will eventually launch a powershell.exe process instead of a Orchestrator.Sandbox.exe process that will not have these limitations.
    • I don’t really like this setup because I have to keep a file outside of source control on each hybrid worker. I also have to maintain a scheduled task on each hybrid worker. Oh well, everything else seems to be working so far and hopefully we can find a way to query this information directly with MS Graph API at some point…

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