Multiple network names scenario
Customer has cluster resource group with multiple network name resources associated with IP address resource. This scenario was described by one of the customers:
Configuring DTC in cluster resource group that also contains the default instance of SQL is our standard practice. This is based on documentation written by Mike Grasso (Microsoft). This practice was never question during the Best Practice Review done by Microsoft either and is the reason why it remains same over the years.
Cluster aware application monitoring requires discovering instance of “Virtual Server” while targeting discovery of such application to this instance. In OpsMgr 2007, definition of Virtual Server is cluster resource group with network name and IP address properties.
Previous releases discovered only single instance of Virtual Server and assigned first network name resource as this instance property. For case study mentioned above, such network name was frequently the one belonging to DTC and not SQL. That is the reason why this approach was often error prone with multiple network names assigned to group and was often causing “loss of monitoring”. Workaround consisting of changing the order of the network name properties is not really feasible and extremely costly to attempt in enterprise environment.
Solution at glance
Override has been introduced to allow each IP address -> Network name dependency discovered as instance of Virtual Server. This override must be turned on. Decision was taken not to change default discovery behavior, based on CSS cases up to date, only specific installations of SQL Server required this feature.
1. Open OpsMgr2007 R2 console.
2. Navigate to Authoring, then Object Discoveries
3. Change the scope to Virtual Server (to simplify location of discovery)
4. Select Windows Clustering Discovery and then select “Override the discovery”
5. Pick Multiple Servers Discovery and change override value to true
Upon dialog closure and configuration reload, multiple Virtual Servers should be discovered where feasible.
Another override that is worth to be mentioned!
Imaging that undesired instance of Virtual Server is discovered after override has been applied. Can I remove it? Definitely …
Use Excluded Servers override (also visible in the picture above)! That override has always been present on all up-to-date releases of OpsMgr 2007 (although I’m not aware of anyone using it). Upon selection, reading description should be self explanatory for user to know what the “value” to use with override is:
String which contains semicolon delimited fully qualified names of virtual servers to be excluded from discovery.
Applying this to customer scenario above, when instance of Virtual Server representing DTC is not required, simply place it’s FQDN into Excluded Servers override value and wait for configuration reload. Such instance will then be deleted and will disappear from views.
HOTFIX allowing this same functionality on OpsMgr 2007 SP1 is at works too for those who will not have OpsMgr 2007 R2 depployed in their environments.