Setting VM CPU scheduler settings with PowerShell [Hyper-V]

  • Article

A while ago I did a number of posts talking about the different controls that are available to you in regards to how Hyper-V schedules virtual machine processor resources (Hyper-V CPU Scheduling–Part 1, Hyper-V CPU Scheduling–Part 2, Hyper-V CPU Scheduling–Part 3 and Hyper-V CPU Scheduling–Part 4).  Today I want to share a PowerShell script that shows you how to configure these settings programmatically:

 # Function for handling WMI jobs / return values
 Function ProcessResult($result, $successString, $failureString)
 {
    #Return success if the return value is "0"
    if ($result.ReturnValue -eq 0)
       {write-host $successString} 
  
    #If the return value is not "0" or "4096" then the operation failed
    ElseIf ($result.ReturnValue -ne 4096)
       {write-host $failureString " Error value:" $result.ReturnValue}
  
    Else
       {#Get the job object
       $job=[WMI]$result.job
  
       #Provide updates if the jobstate is "3" (starting) or "4" (running)
       while ($job.JobState -eq 3 -or $job.JobState -eq 4)
          {write-host $job.PercentComplete "% complete"
           start-sleep 1
  
           #Refresh the job object
           $job=[WMI]$result.job}
  
        #A jobstate of "7" means success
        if ($job.JobState -eq 7)
           {write-host $successString}
        Else
           {write-host $failureString
           write-host "ErrorCode:" $job.ErrorCode
           write-host "ErrorDescription" $job.ErrorDescription}
        }
 }
  
 # Prompt for the Hyper-V Server to use
 $HyperVServer = Read-Host "Specify the Hyper-V Server to use (enter '.' for the local computer)"
  
 # Prompt for the virtual machine to use
 $VMName = Read-Host "Specify the name of the virtual machine"
  
 # Get the management service
 $VMMS = gwmi -namespace root\virtualization Msvm_VirtualSystemManagementService -computername $HyperVServer
  
 # Get the virtual machine object
 $VM = gwmi MSVM_ComputerSystem -filter "ElementName='$VMName'" -namespace "root\virtualization" -computername $HyperVServer
  
 # SettingType = 3 ensures that we do not get snapshots
 $SystemSettingData = $VM.getRelated("Msvm_VirtualSystemSettingData") | where {$_.SettingType -eq 3}
  
 # Get the processor setting data
 $ProcSetting = $SystemSettingData.getRelated("Msvm_ProcessorSettingData") | select -first 1
  
 # Get new values from the user
 $NewReservation = Read-Host "Specify the CPU reserve (from 0-10000) [Currently:"$ProcSetting.Reservation"]"
 $NewLimit = Read-Host "Specify the CPU limit (from 0-10000) [Currently:"$ProcSetting.Limit"]"
 $NewWeight = Read-Host "Specify the CPU weight (from 0-10000) [Currently:"$ProcSetting.weight"]"
  
 # Update ProcSetting with the new values
 $ProcSetting.Reservation = $NewReservation
 $ProcSetting.Limit = $NewLimit
 $ProcSetting.weight = $NewWeight
  
 # Apply the changes to the processor setting data back to the virtual machine
 $result = $VMMS.ModifyVirtualSystemResources($VM, $ProcSetting.GetText(1))
  
 # Process the result
 ProcessResult $result "Updated processor scheduling settings." "Failed to update processor scheduling settings."

Cheers,
Ben

ProcSchedulerSettings.zip