Scripting Microsoft Clusters

• Safely reboot servers in a Microsoft cluster
• Determine which node is active and gracefully moves resources before reboot

We have a number of processes at the grind on Microsoft Windows servers that require 24/7 availability.  However we also have compliance obligations that require us to patch our servers within a certain time of a critical patch coming out.

Enter MSCS, Microsoft Clustering Services! 

We've got a simple active/passive cluster made up of just two servers, so I wrote a script that I configured each node to run before shutting down.  The script checks to see if the node is the active and, if it is, to gracefully transfer all the other resources to the active node before shutting down.

The script takes only the argument of the machine you're wanting to reboot.  Since I've got it configured via GPO and VMware Tools I specify the %COMPUTERNAME% variable as an argument to the script, failover.bat %COMPUTERNAME%.

In a nutshell we're checking for the existence of the quorum drive (Q:\) to determine active/passive status then using the built-in cluster.exe to gracefully transfer any resources running on the node.

Looks a bit like this:

:Allows failover for Microsoft Cluster made up of two nodes. :Makes environmental variables valid for the lifetime of this script only SETLOCAL :------------------------------- :Start of Prerequisites :1. set environmental variable CLUSTERNAME to the name of the cluster set CLUSTERNAME= set CLUSTERNAME=MYCLUSTER :2. Copy psshutdown.exe from Resource Kit (or shutdown.exe) to c:\!failoverscripts directory. :3. This script requires one argument - the name of the server you're rebooting. : (If configured to run as a Scheduled Task or Shutdown script you can call it with the %COMPUTERNAME% argument.) :4. If you have groups beyond the default "Cluster Group" you'll need to add them to the applicable sections. : (Hint: search this script for "Another Cluster Group" and rename with your custom cluster groups.) :End of Prerequisites :------------------------------- If "%1" EQU "" GOTO NOARGS :CHECKIFACTIVE : Checks for existence of Q, the quorum drive. dir q: >nul If not %ERRORLEVEL% EQU 0 GOTO FAILOVERPASSIVE GOTO FAILOVERACTIVE :FAILOVERACTIVE If "%1"=="SERVER1" call :MOVETOTWO If "%1"=="SERVER2" call :MOVETOONE GOTO END :This section moves the groups over to node #1 :MOVETOONE :The default group is "Cluster Group" and contains resources for your cluster. cluster %CLUSTERNAME% group "Cluster Group" /moveto:SERVER1 :Here's the syntax for moving any additional groups you created beyond the default. :cluster %CLUSTERNAME% group "Another Cluster Group" /moveto:SERVER1 GOTO NEXT :This section moves the groups over to node #2 :MOVETOTWO cluster %CLUSTERNAME% group "Cluster Group" /moveto:SERVER2 cluster %CLUSTERNAME% group "Another Cluster Group" /moveto:SERVER2 GOTO NEXT :NEXT :Doesn't restart if there's an error condition If NOT %ERRORLEVEL% EQU 0 GOTO UHOH GOTO RESTARTING :FAILOVERPASSIVE @Echo Node is passive. Restarting... GOTO RESTARTING :RESTARTING :Uses psshutdown from Resource Kit with force, restart, and time (seconds) flags specified. c:\!failoverscripts\psshutdown -f -r -t 30 GOTO END :UHOH :Error handling in here, but the pertinent point is that the restart does not occur. GOTO END :NOARGS @Echo Must specify the server you are wanting to restart. GOTO END :END :Partners with SETLOCAL to end life of environmental variables declared in the script ENDLOCAL