SCOM Discovery Issue: Monitoring Cluster Shared Volumes with the Cluster NetBIOS name longer then 15 Characters doesn’t work

Recently I was asked to investigate why no alerts for a Cluster Shared Volume were received due to it filing up. The short version was that SCOM didn’t discover the CSV’s of the cluster. But other clusters configured in the exact same way on the same hardware ect had the CSV’s discovered and was monitored. Strange.

I stared of in the usual method but manually running discovery, restarting the SCOM agents, flushing the cache and checking the event logs… nothing. So I started digging into the SCOM configuration and see how does discovery work and why would it be failing.

As a cluster is Agentless Monitored I found that the clusters Virtual Server Name was incorrectly discovered. It was missing the last character.

Running: “Get-SCOMAgentlessManagedComputer” and finding the clusters details:

ManagementGroup : XXXXXXX
Computer : XXXXXXXXXSCLUSTE.connecteast.local
LastModified : 14/01/2015 1:20:52 AM
Path :
Name : XXXXXXXXXSCLUSTE.testdomain.local
DisplayName : XXXXXXXXXSCLUSTE.testdomain.local
HealthState : Uninitialized
PrincipalName : XXXXXXXXXSCLUSTE.testdomain.local
ComputerName : XXXXXXXXXSCLUSTE
Domain : testdomain
IPAddress : 10.10.1.100
ProxyAgentPrincipalName : XXXXXPRDHYP26.testdomain.local
Id : f345538e-03b8-f673-da83-2bd2f49a53a8
ManagementGroupId : f71ed7ba-0ae9-f130-8b74-11fda2c11ba1

 

Doing some more checking on the cluster I found that the Name (NetBIOS name) and DNS name didn’t match. By running this command on one of the Hyper-V servers I was able to verify this dependency:

 

Get-ClusterResource -Name “Cluster Name” | Get-ClusterParameter

Object              Name                Value               Type

——              —-                —–               —-

Cluster Name        Name                XXXXXXXXXCLUSTE     String

Cluster Name        DnsName             XXXXXXXXXCluster      String

Cluster Name        Aliases                                 String

 

Then bringing my attention to the discovery rule/scripts I found in the management pack “Microsoft.Windows.Server.ClusterSharedVolumeMonitoing” the XML’s discovery script for CSV’s . The function described in the MP where I think the relationship is breaking is:

‘****************************************************************************************************************
‘   FUNCTION:       DiscoverClusterName
‘   DESCRIPTION:    Discover instances of the relationship class
‘                   ‘Microsoft.Windows.Server.ClusterSharedVolumeMonitoring.Microsoft.Windows.Cluster.Contains.Microsoft.Windows.Cluster.VirtualServer’.
‘   PARAMETERS:     IN String strTargetComputer: principal name of the targeted ‘Microsoft.Windows.Cluster.VirtualServer’ instance.
‘                   OUT Object objDiscoveryData: initialised DiscoveryData instance
‘   RETURNS:        Boolean: True if successful
‘****************************************************************************************************************

So if the discovery of the Virtual Computer Class for the cluster is incorrect (IE “XXXXXXXXXCLUSTE”) and the cluster name used is “XXXXXXXXXCluster” it wont discover any relationship to the CSV’s as its using the incorrect name of the cluster.

The only solution I can think of is to rename the cluster so that the NetBIOS name and DNS name match or if Microsoft Update the discovery to allow for this condition when discovering.

On that Note Microsoft don’t recommend naming clusters or servers longer than 15 characters.

What we have a secondary monitoring (PRTG) system which I was able to configure the CSV’s to be monitored by (only limitation of this is that it isn’t cluster aware and monitoring from only 1 node.)

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