LucD notes

You should know by now that alarms are a powerful tool to help you manage and monitor your vSphere environment.  But in my opinion there is a basic operation missing.

There is no easy way to move an alarms from one entity to another entity. No drag-and-drop in the vSphere Client, no Move-Alarm cmdlet in PowerCLI.

A practical example, you have developed this fantastic new alarm and for testing purposes you had defined it on a single virtual machine. Now the tests are done and your alarm is ready for production. But there is apparently no easy way to move your new alarm to the root of your vSphere environment.

Luckily we have PowerCLI and we can easily create a function to fill this gap.

The function is called Move-Alarm and has the following syntax:

Move-Alarm -Alarm <Alarm> -From <ViContainer> -To <ViContainer[]> -DeleteOriginal

-Alarm: the MoRef of the Alarm object you want to move
-From: the ViContainer from where the alarm should be moved
-To: one or more ViContainer objects to which the alarm should be moved
-DeleteOriginal: a switch that determines what happens with the original alarm. Default is $false

While using the script I discovered that the length of the name of an alarm can not exceed 80 characters. This seems to be an undocumented “feature”.

A second problem in the original script was that when you “move” to more than one destination, there would be an error message on the second “move”. That was because you can not have two alarms with the same name in your vCenter. The solution I used was to add the name of the destination entity as a suffix to the name of the new alarm.

The third problem was the Status property in each EventAlarmExpression object. Since the script copies the AlarmInfo object from the “from” alarm to the AlarmSpec object for the “to” alarm, the Status property has to blanked out explicitly.

Set-Variable -Name alarmLength -Value 80 -Option "constant"

$from = Get-Folder -Name "Datacenters" | Get-View
$to1 = Get-Folder -Name "Folder1" | Get-View
$to2 = Get-Folder -Name "Folder2" | Get-View

function Move-Alarm{
	param($Alarm, $From, $To, [switch]$DeleteOriginal = $false)

	$alarmObj = Get-View $Alarm
	$alarmMgr = Get-View AlarmManager

	if($deleteOriginal){
		$alarmObj.RemoveAlarm()
	}
	else{
		$updateAlarm = New-Object VMware.Vim.AlarmSpec
		$updateAlarm = $alarmObj.Info
		$oldName = $alarmObj.Info.Name
		$oldState = $alarmObj.Info.Enabled
		$oldDescription = $alarmObj.Info.Description
		$suffix = " (moved to " + ([string]($to | %{$_.Name + ","})).TrimEnd(",") + ")"
		if(($oldName.Length + $suffix.Length) -gt $alarmLength){
			$newName = $oldName.Substring(0, $alarmLength - $suffix.Length) + $suffix
		}
		else{
			$newName = $oldName + $suffix
		}
		$updateAlarm.Name =  $newName
		$updateAlarm.Enabled = $false
		$updateAlarm.Description += ("`rOriginal name: " + $oldName)
		$updateAlarm.Expression.Expression | %{
			if($_.GetType().Name -eq "EventAlarmExpression"){
				$_.Status = $null
				$needsChange = $true
			}
		}

		$alarmObj.ReconfigureAlarm($updateAlarm)

		$alarmObj.Info.Name = $oldName
		$alarmObj.Info.Enabled = $oldState
		$alarmObj.Info.Description = $oldDescription
	}

	$newAlarm = New-Object VMware.Vim.AlarmSpec
	$newAlarm = $alarmObj.Info

	$oldName = $alarmObj.Info.Name
	$oldDescription = $alarmObj.Info.Description

	foreach($destination in $To){
		if($To.Count -gt 1){
			$suffix = " (" + $destination.Name + ")"
			if(($oldName.Length + $suffix.Length) -gt $alarmLength){
				$newName = $oldName.Substring(0, $alarmLength - $suffix.Length) + $suffix
			}
			else{
				$newName = $oldName + $suffix
			}
			$newAlarm.Name = $newName
			$newAlarm.Description += ("`rOriginal name: " + $oldName)
		}
		$newAlarm.Expression.Expression | %{
			if($_.GetType().Name -eq "EventAlarmExpression"){
				$_.Status = $null
				$needsChange = $true
			}
		}

		$alarmMgr.CreateAlarm($destination.MoRef,$newAlarm)
		$newAlarm.Name = $oldName
		$newAlarm.Description = $oldDescription
	}
}

$alarmMgr = Get-View AlarmManager

$alarms = $alarmMgr.GetAlarm($from.MoRef)
$alarms | % {
	Move-Alarm -Alarm $_ -From (Get-View $_) -To $to1,$to2 -DeleteOriginal:$false
}

Line 1: The maximum length of the name of an Alarm defined as a constant.

Line 3-5: Variables that will be used later on in the script as parameters to the function. In the sample I’m moving all alarms from the vCenter root (hidden entity “Datacenters”) to two folders called “Folder1″ and “Folder2″

Line 8: Note that the function doesn’t use strongly types parameters for the -From and -To parameters. This is because the ViObjects on which alarms can be defined can be of several types (Datacenter, Folder, HostSystem…). This also allows to pass an array of ViObjects for the -To parameter.

Line 14: If the -DeleteOriginal switch is set to $true, the original alarm will be deleted.

Line 17-35: If the -DeleteOriginal switch is set to $false the original Alarm will be kept but it will be renamed since there can not be multiple alarms with the same name.

Line 24,48: If the length of name with the suffix exceeds 80 characters, the script will remove sufficient characters from the original alarmname to be able to add the suffix.

Line 29: If the original alarm is kept it will be renamed. The original will get a suffix “(moved to <dest>)”

Line 30: If the original alarm is kept it will be “disabled”.

Line 31,54: The script adds the original alarmname to the Description field.

Line 32-37,64-69: Since the script copies the AlarmSpec object from the original alarm, the Status field for all the EventAlarmExpression objects needs to blanked out.

Line 52: The -To parameter is handled in a foreach loop since the function allows more than one destination. The function can be used as a 1-to-n move in this case.

Line 80-81: A sample use case of the Move-Alarm function. All Alarms defined in the root of the vCenter will be “moved” to “Folder1″ and “Folder2″. The original Alarm will not be deleted but it will be renamed and disabled.

Before the run of the above sample use of the script, the alarms defined on the vCenter root look like this.

After the first call of the Move-Alarm function the first alarm has been changed and disabled.

And on both target folders the alarm has been created as this screenshot from the alarms on Folder1 shows.

This is a rather simple function but it can be quite useful at times. I hope it can be of use to some of you.