Poweroff and Poweron 1000 VMs in Parallel

[shahb]

Hi

I've a maintenance is coming up for which I need to shutdown 1000+ VMs and once the Maintenance is complete, Need to start those VMs back on.

I've a list of 1000 VMs and I can run in for loop but that will take hours to shutdown these VMs and I only have 2 hours of Maintenance window, Can someone please help ?

Here is the script which I got from the community and it works as expected but it runs serially.

foreach ($vmlist in (Get-Content -Path C:\vmlist1.txt)){

$vm = Get-VM -Name $vmlist

Start-VM -VM $vm -Confirm:$false -RunAsync

}

Thanks & Regards

[LucD]

You can use the Start-Job cmdlet to launch these cmdlets in the background.

You probably want to impose a maximum number of jobs to run in the background, hence the MaxJobs test.

$script = {

   param(

   [string]$VMName,

   [string]$vcId

   )

   Connect-VIServer -Session $vcId

   Get-VM -Name $VMName | Shutdown-VMGuest -Confirm:$false

}

$fileName = '.\input.csv'

$MaxJobs = 10

Import-Csv -Path $fileName | ForEach-Object -Process {

   $jobs = @()

   while ($jobs.Count -le $MaxJob) {

   $jobs += (Start-Job -ScriptBlock $script -ArgumentList $_.VMName, $global:DefaultVIServer.SessionId)

   }

   Wait-Job -Job $jobs

}

[shahb]

Thank you LuCD. Greatly appreciate your quick response.

I'm not great at powercli so please bear me if my questions are silly.

1) When I run it , I get the following error -

2) Connect-VIServer -Session $vcId ->  Where do we put vCenter name to login to ?

on the other hand, can we just login to vCenter and then just run the script and remove tht line ?

Thanks a lot LuCD for your help.

[LucD]

1) Sorry, I had a type in there.

The Wait-Job -Job $jobs.Id should have been Wait-Job -Job $jobs.Id.

I corrected the code above.

2) In a background job you don't inherit the connection to the vCenter.

That is why the SessionId is passed to the background job.

And also why we have the Connect-VIServer in there.

To run the script, connect to your vCenter.
Then run the script.

It will pass the SessionId to the background jobs.

[shahb]

Thanks again LuCD

Understood #2 Greatly appreciate it.

I changed the Wait-Job line to Wait-Job -Job $jobs and I still get the same error .

Sorry for bugging you.

[LucD]

Are you sure about the same error?

Just tried it, and it works for me.

Which PowerShell version are you running (check $PSVersionTable)?

[shahb]

Yes, Here is the error -

[LucD]

Can you attach the script as you are running it?

[shahb]

Hi LuCD

Attached.

Thank You

[LucD]

You are missing a closing brace at the end of the script.
Does your CSV contain a column with the name VMname?

The CSV should look something like this

VMName

vm1

vm2

vm3

[shahb]

Yes, I added VMName and closing brace . Sorry that was missing.

Here is the new error -

[LucD]

I have a different version, can you try that one?

$script = {

   param(

   [string]$VMName,

   [string]$vcId

   )

   Connect-VIServer -Session $vcId

   Get-VM -Name $VMName | Shutdown-VMGuest -Confirm:$false

}

$fileName = '.\input.csv'

$MaxJobs = 10

$jobs = @()

Import-Csv -Path $fileName | ForEach-Object -Process {

   if ($jobs.Count -le $MaxJob) {

   Write-Host "Job for $($_.VMName)"

   $job = (Start-Job -Verbose -ScriptBlock $script -ArgumentList $_.VMName, $global:DefaultVIServer.SessionId)

   Write-Host "`tStarted job $($job.Id)"

   Write-Host "`tRunning jobs $($jobs.Count)"

   $jobs += $job

   }

   else {

   Wait-Job -Job $jobs

   $jobs = @()

   }

}

[shahb]

Thanks again for your time and support LuCD

Here is the error after new code -

[LucD]

Did none of the Write-Host lines produce any output?

[shahb]

Unfortunately not LuCD

[LucD]

That would mean that the following returns nothing.

Can you check?

$fileName = '.\input.csv'

Import-Csv -Path $fileName

[shahb]

Here is my input.csv

VMName

cvp-master1

cvp-master2

its in the same path as the script.

$fileName = '.\input.csv'

Am I doing anything wrong here?

[LucD]

The relative path starts from your current location.

Did you try the code I just gave?

Does it return the content of the CSV?

[shahb]

Yes, it does

[LucD]

I think I found it, there is a typo (missing 's' in $MaxJobs).

The line

if ($jobs.Count -le $MaxJob) {

should say

if ($jobs.Count -le $MaxJobs) {