Archive for February, 2010

I was asked whilst on a customer site to work out who had created a VM, this is a common question in most environments where admin rights are the normal and creating a VM is as easy as creating a new word document.

After trawling through the logs for a couple of minutes I found the creator and told the customer, easy enough I guess but how could we make this easier ?

The answer to that question will be no surprise to most readers of this blog….. PowerCLI !

With a quick script and resolving the user account in AD, I was able to add a custom field to each VM letting me know who created the VM and when it was created, all displayed in the annotations of each VM as seen below:

Connect-VIServer MYVISERVER
# Uncomment the next line to test this script and tell you what it would do !
# $WhatIfPreference = $true
if (-not (Get-PSSnapin VMware.VimAutomation.Core -ErrorAction SilentlyContinue)) {
	Add-PSSnapin VMware.VimAutomation.Core
}
if (-not (Get-PSSnapin Quest.ActiveRoles.ADManagement -ErrorAction SilentlyContinue)) {
	Add-PSSnapin Quest.ActiveRoles.ADManagement
}

$VMs = Get-VM | Sort Name
$VM = $VMs | Select -First 1
If (-not $vm.CustomFields.ContainsKey("CreatedBy")) {
	Write-Host "Creating CreatedBy Custom field for all VM's"
	New-CustomAttribute -TargetType VirtualMachine -Name CreatedBy | Out-Null
}
If (-not $vm.CustomFields.ContainsKey("CreatedOn")) {
	Write-Host "Creating CreatedOn Custom field for all VM's"
	New-CustomAttribute -TargetType VirtualMachine -Name CreatedOn | Out-Null
}
Foreach ($VM in $VMs){
	If ($vm.CustomFields["CreatedBy"] -eq $null -or $vm.CustomFields["CreatedBy"] -eq ""){
		Write-Host "Finding creator for $vm"
		$Event = $VM | Get-VIEvent -Types Info | Where { $_.Gettype().Name -eq "VmBeingDeployedEvent" -or $_.Gettype().Name -eq "VmCreatedEvent" -or $_.Gettype().Name -eq "VmRegisteredEvent" -or $_.Gettype().Name -eq "VmClonedEvent"}
		If (($Event | Measure-Object).Count -eq 0){
			$User = "Unknown"
			$Created = "Unknown"
		} Else {
			If ($Event.Username -eq "" -or $Event.Username -eq $null) {
				$User = "Unknown"
			} Else {
				$User = (Get-QADUser -Identity $Event.Username).DisplayName
				if ($User -eq $null -or $User -eq ""){
					$User = $Event.Username
				}
				$Created = $Event.CreatedTime
			}
		}
		Write "Adding info to $($VM.Name)"
		Write-Host -ForegroundColor Yellow "CreatedBy $User"
		$VM | Set-CustomField -Name "CreatedBy" -Value $User | Out-Null
		Write-Host -ForegroundColor Yellow "CreatedOn $Created"
		$VM | Set-CustomField -Name "CreatedOn" -Value $Created | Out-Null
	}
}

The script is fairly straight forward, a few caveats are worth mentioning though:

• This script uses the Quest AD cmdlets to resolve the username in AD, if you don’t have these installed then you can either install them or use the Microsoft AD cmdelts or I have a small function which will do the same thing, I previously used this here.
• This may take a long time if the VM was created a long time ago as unfortunately the Get-VIEvent cmdlet does not have a way to start from the beginning of the events so I need to retrieve all events for that VM and then filter on them.
• If the VM’s were removed from the virtual center and then re-added it will have the name of the person who re-imported or added the VM, not the original creator.

Once we have the information added to the VM’s we can of course do some cool reporting, like who created the VM’s:

Get-VM | Select Name -ExpandProperty CustomFields | Where {$_.key -eq "CreatedBy"} | Out-GridView

Or even who created the most VMs:

Get-VM | Select Name -ExpandProperty CustomFields | Where {$_.key -eq "CreatedBy"} | Group-Object | Select Count, Name | Sort Count -Descending |Out-GridView 

The use cases for PowerCLI and automation continue to amaze me, a couple of nice use cases I have seen recently involve automating the deployment of VM’s for various reasons.

The first reason, performance, what happens when a VM which is sat there for most of the year suddenly becomes busy and doesn’t have enough resources to satisfy whatever service it is trying to provide, do you add more ram, more CPU, what happens when you get to the maximum 8 CPU’s and the maximum vSphere VM memory of 255GB, do you then deploy a second VM and a third etc etc

Take this scenario into consideration:

You work in the UK for a county wide radio station, most of the time your virtualised cluster of web servers is sat there doing nothing, serving the odd hit now and again…but then it snows !

As we know, the UK can not handle snow at the best of times, the country grinds to a halt, the only means of knowing if your children’s school is closed is to check the local radio station’s website….enter our problem.

As you are also snowed in and unable to make it to the office you are unable to build the VM’s and add them to the cluster to allow the existing VMs which are now stuck on 100% CPU usage whilst you dig your car out.

Wouldn’t it be nice if we could have an automated response to this ? I held aloft my sword and said “With the power of CLI” (He-Man fans will get this).

I have two methods for this, the first one is a great script and the second is a bit of fun to show exactly how powerful PowerShell and PowerCLI can be. More >