Hyper-V Replication Status for PRTG

Recently I wanted to add better monitoring of the Primary and Extended Hyper-V replication of our environment. Since our primary monitoring tool is PRTG I went looking for a sensor for this. There is no built in sensor, however I did find this custom PowerShell script on the PRTG forums; Monitoring Hyper-V Replication | Paessler Knowledgebase. This script pulls the current state of the Hyper-V primary replication. I was able to also differentiate between Primary and Extended replication by adding an IF statement to the script.

if ($Name.ReplicationRelationshipType -like "Simple")
--or--
if ($Name.ReplicationRelationshipType -like "Extended")

This provided the basic monitoring that I needed, but it has a couple of issues. Hyper-V doesn’t consider the replication in error until 20% of the cycles for monitored time period. I wanted to get an earlier warning and also see the trends. Digging around some more, I found the Measure-VMReplication command which gives the number of successful and missed replication cycles. This allows me to retrieve exactly the data I needed. One wrinkle is that instead of just getting the “Simple” or “Extended” replication from the target, I found I have to go to the replication source for the correct counts. To do this I needed to be able to provide a list of hosts in the parameter.

First retrieve the parameter, start the XML, and split the parameter into the list of servers

#Takes list of servers in quotes delimited by comma as a parameter
Param(
[string]$Hypervservers
)
$ErrorActionPreference = "SilentlyContinue"
#start writing in XML
Write-Host 	"<prtg>"
#Split the parameter into list of servers
$ServerList = $Hypervservers.Split(",")

The script then loops through each of the servers to retrieve the statistics for each VM. One problem that I had is that the remote PowerShell session would not retrieve the statistics form a different host. I solved this by opening a new session for each host. To have the script retrieve Extended instead of Primary replication, change the ReplicationRelationshipType to “Extended”.

foreach ($Hypervserver in $ServerList) {
	#I had issues getting the remote server data unless I opened the remote session
#to the specific server I was getting the data about.
	#Open a new remote PS session
	$Session = New-PSSession -computername $Hypervserver
	Import-PSSession $Session -Module Hyper-V -warningaction "SilentlyContinue"

#Get the replication data
	$VMReplication = Measure-VMReplication  -computername $Hypervserver  -ReplicationRelationshipType Simple | select VMname,SuccessfulReplicationCount,MissedReplicationCount

#Write the data for each VM as a PRTG channel
	foreach ($Name in $VMReplication) {
		#I couldn't get PRTG to display the percent with only 2 decimal places, so I rounded here
		$AvgSuccess = [math]::Round(($Name.SuccessfulReplicationCount / ($Name.SuccessfulReplicationCount + $Name.MissedReplicationCount))*100,0)
		$VM = $Name.VMName

		#Write the Channel
		Write-Host 	"<result>"
					"<channel>$VM</channel>"
					"<Unit>Percent</Unit>"
					"<Float>1</Float>"
					"<DecimalMode>2</DecimalMode>"
					"<value>$AvgSuccess</value>"
					"<LimitMinWarning>90</LimitMinWarning>"
					"<LimitMinError>80</LimitMinError>"
					"<LimitMode>1</LimitMode>"
					"</result>"
	}

#Close the remote PS session so it can be opened to the next host
	Remove-PSSession $Session
}

#Close the XML
Write-Host 	"</prtg>"

#Exit code 0 so PRTG knows the script ran successfully
Exit 0

After setting up the Advanced Custom Sensor I can now track on a per-VM basis the replication results. Download the full script here: www.xbyte.com/replicationstatus.zip

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