Tag: host alarms

In a previous write-up I discussed how to check the Alarm status of ESX hosts in a cluster. Let’s take it a step further and check how we can enable the alarms on an ESX host in order to automate it – so that alarms will be enabled on ESX hosts for eternity, as a healthy environment should! No longer shall we be in doubt whether we forgot to enable alarms in a ESX host after working on it! This is actually very simple! Lets get to it!

Here I will be talking about enabling alarms on all hosts in the vCenter (not on a particular cluster). You can put this script on a task scheduler to keep it running on a schedule so that Alarms will be enabled periodically throughout the day.

Step 1: Getting the list of ESX hosts whose alarms are disabled

$alarm_disabled_hosts = Get-VMHost | Where-Object {$_.extensiondata.AlarmActionsEnabled -eq $false}

This was discussed in the previous post, so I won’t discuss this at length. Its a pretty self evident line anyway 😉 With Get-VMHost called raw and bare naked like that we loop through all hosts piped to the where-object clause which checks for the AlarmActionsEnabled extension data.

Step 2: Enable them alarms!

The Service Instance in charge of handling alarms in the vCenter is the Alarm manager. So lets get a view of that manager entity to call on its management capabilities.

$alarmMgr = Get-View AlarmManager

Now that we have called on the Alarm Manager to the $alarmMgr variable, we can also call on EnableAlarmActions to enable alarms from our list of hosts whose alarms are disabled

$alarmMgr.EnableAlarmActions(<host_name>.Extensiondata.MoRef,$true)

Above line enables the alarms on the host that we specify

Let’s see how we can put all this together in one full script:

Connect-VIServer <vCenter>

$alarm_disabled_hosts = Get-VMHost | Where-Object {$_.extensiondata.AlarmActionsEnabled -eq $false}

$alarmMgr = Get-View AlarmManager


ForEach ($hosts in $alarm_disabled_hosts){

    $alarmMgr.EnableAlarmActions($hosts.Extensiondata.MoRef,$true)
    
}

This would enable alarms on all ESX hosts whose alarms are currently disabled.

Extra Credit : Skip hosts in maintenance mode

If the host is in maintenance mode, chances are that you are working on some error on the host and you will have to keep those alarms disabled. So for extra credit let’s see how we can modify the script to skip the hosts in maintenance mode:

Connect-VIServer <vCenter>

$alarmMgr = Get-View AlarmManager


ForEach ($hosts in $alarm_disabled_hosts){

    if ($hosts.ConnectionState -eq "Maintenance"){
        Write-Host "$hosts in maintenance mode, alarms will remain disabled"
    }

    else{
        Write-Host "Enabling alarms in $hosts"
        $alarmMgr.EnableAlarmActions($hosts.Extensiondata.MoRef,$true)
    }

}

And thats it! Keep this running on a schedule and you can be sure your environment has constant monitoring enabled.

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And as always, Happy scripting!