How to generate an alert in Microsoft OMS when a computer is down or unreachable

Hi everyone, we have been seeing a lot of votes for "Alert if the Machine is down/Unreachable" in the User Voice for Microsoft Operations Management Suite (OMS) so while we’re working on this feature, I thought I would go ahead and share a workaround for this that you can use in the meantime. As you’ll see, it’s actually fairly simple to make OMS send an email alert when the machine is down.

So the main question here is, “How do we check if the machine is down?” We can’t just check whether we’re receiving a heartbeat from the server because the agent service (Microsoft Monitoring Agent), which is sending the heartbeat, might be down and not the machine? To deal with that scenario, we must also ping the server itself.

With that in mind, let’s break it down into two parts:

  • Checking the heartbeat
  • Pinging the server

Check the heartbeat

This is fairly simple. All we need to do is go to Log Search in the OMS portal and search for Heartbeat. You can either write the query for this, or you can use the portal to do it. Heartbeat is a type of log, and you can select it under the types on the left side. Here is an example:

  • Go to the OMS portal.
  • Go to Log Search.
  • Type * in the search box and search so that it will search for all the logs.
  • Now you will see this in the left hand side:

Log Search

  • Now select Heartbeat here:

Heartbeat selection in Log Search

  • Now you can see the heartbeat for all of the computers that are monitored by OMS.
  • You will see the computer names on the left side, so go ahead and select the computer that you want to monitor:

Selecting computer names in Log Search

  • Now the query in the search box will look something like this:

* (Type=Heartbeat) (Computer=OMSTESTRC)

This will search for all logs with that computer name and type as Heartbeat.

  • To optimize our query, remove the *. Now we can generate an alert for this by clickingAlert:

The Alert button

  • This will take you to the Add Alert Rule page with the query already in place:

Add Alert Rule page

  • Give it a Name, Description and Severity.
  • Set Time window and Generate alert based on to a value greater than 2. This is because Microsoft Monitoring Agent sends a heartbeat to OMS every minute (every 60 seconds). If we are missing more than two heartbeats, it will generate this alert. Usually we recommend setting this to 5 minutes.

Now we have alerts generated whenever we don't receive a heartbeat for a certain amount of time, so next we need to look at how we can ping the computer using OMS.

Pinging the server

To ping the computer, we need to have access to the local (on-premises) environment so that we can reach the computer. To automatically ping the computer after our alert is generated, we have the option of attaching a Runbook to the alert. Here is where you see it on the Alert page:

Attaching a runbook on the Alert page

NOTE: To attach a runbook, you will need an Automation account first. For more information, see How to Setup and Configure Microsoft Azure Automation Runbooks.

There are two types of runbooks that you can attach: An Azure Runbook and a Hybrid Runbook Worker.

Selecting a runbook

So this should answer our first question, which is “How do I get access of the local (on-premise) environment? ” The answer is a Hybrid Runbook Worker!

What is Hybrid Runbook Worker? Runbooks in Azure Automation cannot access resources in your local data center because they run in the Azure cloud. The Hybrid Runbook Worker feature of Azure Automation allows you to run Runbooks on computers that are located in your datacenter to manage local resources. These Runbooks are stored and managed in Azure Automation and then delivered to one or more on-premises computers.

To read more about the Hybrid Runbook Worker, please visit

That documentation also shows how to configure it in your environment so I will not go into depth on that here.

Now, after you have the Hybrid Runbook Worker feature, the question becomes “How do I ping the computer? ” Because there aren't many cmdlets to ping a server using Azure Automation, I went ahead and wrote a script to do that. This script not only pings the computer, but it also sends an email with the results. This is a PowerShell workflow script, and you can modify the script for your needs and requirements.

The script

workflow Ping { InlineScript { function send-email([string]$R){

Write-output "Ping was successful" Write-output "Sending email" $Output = $Server+" is Reachable" $Emailoutput = $output $CredUser = "" $CredPassword ="Password" $SMTPServer = "" $EmailTo = "" $Subject = "VM Status" $emailCreds = New-Object System.Management.Automation.PSCredential($CredUser,(ConvertTo-SecureString -String $CredPassword -AsPlainText -Force)) Send-MailMessage -from $CredUser -to $EmailTo -Subject $Subject -Body $Emailoutput -Credential $emailCreds -SmtpServer $SMTPServer -usessl -port 587


function send-emailUR([string]$UR){

Write-output "Ping unsuccessful" Write-output "Sending email" $Output = $Server+" is Unreachable" $Emailoutput = $output $CredUser = "" $CredPassword ="Password" $SMTPServer = "" $EmailTo = "" $Subject = "VM Status" $emailCreds = New-Object System.Management.Automation.PSCredential($CredUser,(ConvertTo-SecureString -String $CredPassword -AsPlainText -Force)) Send-MailMessage -from $CredUser -to $EmailTo -Subject $Subject -Body $Emailoutput -Credential $emailCreds -SmtpServer $SMTPServer -usessl -port 587


#This function will perform a simple, small size #single packet ping of a machine and return

function ping-host([string]$server) { if ([string]::IsNullOrEmpty($server) ) {return $false}

#ping first for reachability check

$po = New-Object net.NetworkInformation.PingOptions $po.set_ttl(64) $po.set_dontfragment($true) [Byte[]] $pingbytes = (65,72,79,89) $ping = new-object Net.NetworkInformation.Ping $savedEA = $Erroractionpreference $ErrorActionPreference = "silentlycontinue" $pingres = $ping.send($server, 1000, $pingbytes, $po) if (-not $?) {return $false} $ErrorActionPreference = $savedEA

#Calling email functions if ($pingres.status -eq "Success") { send-email abc } else { send-emailUR bcd }


#Calling the Ping function ping-host ServerName




When you use this script, just be sure to modify the appropriate sections for your environment.

Once you have this Runbook in the Automation account, go ahead and attach it as a Hybrid Runbook Worker, and you should be good to go. Now you will receive emails for heartbeat not found and Server Unreachable messages as well!

I hope you found this helpful, and any feedback would be appreciated.

I’d also like to extend special thanks to my colleague Jeff Fanjoy for helping me and mentoring me through this process.


Rupanter Chhabra
Support Engineer
Azure | Manageability & Security Division
Customer Service & Support (CSS)