PowerCLI: Script to Schedule Memory and or vCPU up/downgrade

After creating the Restart-VMs.ps1 script, I also created a script to schedule vHardware changes. With this script, you’re able to upgrade or downgrade the amount of memory and or the amount of vCPU’s of a VM. Just lik the restart script, you can schedule this script and change the recommended parameters.

These are the parameters you need to supply to the script. The first two parameters are mandatory. When you supply all the parameters, you are able to add/remove Memory and add/remove vCPU’s.

-vCenter	enter the vCenter server you want to connect to. It’s possible to connect to multiple vCenter servers.
-vmName	enter the name of the VM you want
-MemoryMB	enter the amount of memory you want to add or remove from the VM. Be sure you enter the amount in MB.
-MemoryOption	Supply the option add or remove.
-CPUCount	Enter the amount of vCPU’s you want to add or remove from the VM.
-CPUOption	Supply the option add or remove.

This is how the script works.

1. Connect to vCenter
2. Shutdown the selected VM
3. Add/remove memory and or vCPU’s
4. Poweron the selected VM
5. Disconnect vCenter

Now it’s time for an example. I have a VM called NAGIOS and needed to remove 512MB RAM and needed to add an extra vCPU. So I started the script with the following parameters:

.\Change-VM_Memory_CPU_Count.ps1 -vCenter vc01.ict-freak.local -vmName NAGIOS -MemoryMB 512 -MemoryOption Remove -CPUCount 1 -CPUOption Add

The VM is powered off and the memory is downgraded to 1024MB RAM and the total number of vCPU’s upgraded to 2.

You can download the script below.

The script:

###################################################################
#
# Change-VM_Memory_CPU_Count.ps1
#
# -MemoryMB the amount of Memory you want 
#  to add or remove from the VM in MB
# -MemoryOption Add/Remove
# -CPUCount the amount of vCPU's you want 
#  to add or remove from the VM
# -CPUOption Add/Remove
#
# Example:
# .\Change-VM_Memory_CPU_Count.ps1 -vCenter vc01 
# -vmName NAGIOS -MemoryMB 512 -MemoryOption Add 
# -CPUCount 1 -CPUOption Remove
#
# Version 1.0 May 2010 Arne Fokkema www.ict-freak.nl @afokkema

#
####################################################################

param(
    [parameter(Mandatory = $true)]
    [string[]]$vCenter,
    [parameter(Mandatory = $true)]
    [string]$vmName,
    [int]$MemoryMB,
    [string]$MemoryOption,
    [int]$CPUCount,
    [string]$CPUOption
)    

function PowerOff-VM{
    param([string] $vm)
    
    Shutdown-VMGuest -VM (Get-VM $vm) -Confirm:$false | Out-Null
    Write-Host "Shutdown $vm"
    do {
        $status = (get-VM $vm).PowerState
    }until($status -eq "PoweredOff")
    return "OK"
}

function PowerOn-VM{
    param( [string] $vm)
    
    if($vm -eq ""){    Write-Host "Please enter a valild VM name"}
    
    if((Get-VM $vm).powerstate -eq "PoweredOn"){
        Write-Host "$vm is already powered on"}
    
    else{
        Start-VM -VM (Get-VM $vm) -Confirm:$false | Out-Null
        Write-Host "Starting $vm"
        do {
            $status = (Get-vm $vm | Get-View).Guest.ToolsRunningStatus
        }until($status -eq "guestToolsRunning")
        return "OK"
    }
}

function Change-VMMemory{
    param([string]$vmName, [int]$MemoryMB, [string]$Option)
    if($vmName -eq ""){
        Write-Host "Please enter a VM Name"
        return
    }
    if($MemoryMB -eq ""){
        Write-Host "Please enter an amount of Memory in MB"
        return
    }
    if($Option -eq ""){
        Write-Host "Please enter an option to add or remove memory"
        return
    }

    $vm = Get-VM $vmName    
    $CurMemoryMB = ($vm).MemoryMB
    
    if($vm.Powerstate -eq "PoweredOn"){
        Write-Host "The VM must be Powered Off to continue"
        return
    }
    
    if($Option -eq "Add"){
        $NewMemoryMB = $CurMemoryMB + $MemoryMB
    }
    elseif($Option -eq "Remove"){
        if($MemoryMB -ge $CurMemoryMB){
            Write-Host "The amount of memory entered is greater or equal than 
            the current amount of memory allocated to this VM"
            return
        }
        $NewMemoryMB = $CurMemoryMB - $MemoryMB
    }

    $vm | Set-VM -MemoryMB $NewMemoryMB -Confirm:$false
    Write-Host "The new configured amount of memory is"(Get-VM $VM).MemoryMB
}

function Change-VMCPUCount{
    param([string]$vmName, [int]$NumCPU, [string]$Option)
    if($vmName -eq ""){
        Write-Host "Please enter a VM Name"
        return
    }
    if($NumCPU -eq ""){
        Write-Host "Please enter the number of vCPU's you want to add"
        return
    }
    if($Option -eq ""){
        Write-Host "Please enter an option to add or remove vCPU"
        return
    }

    $vm = Get-VM $vmName    
    $CurCPUCount = ($vm).NumCPU
    
    if($vm.Powerstate -eq "PoweredOn"){
        Write-Host "The VM must be Powered Off to continue"
        return
    }
    
    if($Option -eq "Add"){
        $NewvCPUCount = $CurCPUCount + $NumCPU
    }
    elseif($Option -eq "Remove"){
        if($NumCPU -ge $CurCPUCount){
            Write-Host "The number of vCPU's entered is higher or equal 
            than the current number of vCPU's allocated to this VM"
            return
        }
        $NewvCPUCount = $CurCPUCount - $NumCPU
    }

    $vm | Set-VM -NumCPU $NewvCPUCount -Confirm:$false
    Write-Host "The new configured number of vCPU's is"(Get-VM $VM).NumCPU
}

#######################################################################################
# Main script
#######################################################################################

$VIServer = Connect-VIServer $vCenter
If ($VIServer.IsConnected -ne $true){
    Write-Host "error connecting to $vCenter" -ForegroundColor Red
    exit
}

if($MemoryMB -or $CPUCount -ne "0"){
    $poweroff = PowerOff-VM $vmName
    if($poweroff -eq "Ok"){
    Write-Host "PowerOff OK"

        if($MemoryMB -ne "0"){
            if($MemoryOption -eq " ") {Write-Host "Please enter an option to add or remove memory"}
            else{
                Change-VMMemory $vmName $MemoryMB $MemoryOption
            }
        }

        if($CPUCount -ne "0"){
            if($CPUOption -eq " ") {Write-Host "Please enter an option to add or remove cpu"}
            else{
                Change-VMCPUCount $vmName $CPUCount $CPUOption
            }
        }
        
        $poweron = PowerOn-VM $vmName
        if($poweron -eq "Ok"){
            Write-Host "PowerOn OK"}
    }
}

Disconnect-VIServer -Confirm:$false