The World According to Mitch

When I started evangelizing Windows Server 2012 for Microsoft, there was a long list of features that I was always happy to point to.  There are a few of them that I have never really gone into detail on, that I am currently working with.  Hopefully these articles will help you.

Cluster Aware Updates (CAU) is a feature that does exactly what it says – it helps us to update the nodes in a Failover Cluster without having to manually take them down, put them into maintenance mode, or whatever else.  It is a feature that works in conjunction with our patch management servers as well as our Failover Cluster.

I have written extensively about Failover Clusters before, but just to refresh, we need to install the Failover Clustering feature on each server that will be a cluster node:

PS C:\Install-WindowsFeature –Name Failover-Clustering –IncludeManagementTools –ComputerName <ServerName>

We could of course use the Server Manager GUI tool, but if you have several servers it is easier and quicker to use Windows PowerShell.

Once this is done we can create our cluster.  Let’s create a cluster called Toronto with three nodes:

PS C:\New-Cluster –Name Toronto –Node Server1, Server2, Server3

This will create our cluster for us and assign it a dynamic IP address.  If you are still skittish about dynamic IP you can add a static IP address by modifying your command like this:

PS C:\New-Cluster –Name Toronto –Node Server1, Server2, Server3 –StaticAddress 10.10.10.201

Great, you have a three-node cluster.  So now onto the subject at hand: Cluster Aware Updates.

You would think that CAU would be a default behaviour.  After all, why would anyone NOT want to use it? Nonetheless, you have to actually enable the role feature.

PS C:\Add-CauClusterRole –EnableFirewallRules

Notice that we are not using the –ComputerName switch.  That is because we do not install the role service to the servers but to the actual cluster.  You will be asked: Do you want to add the Cluster-Aware Updating clustered role on cluster “Toronto”? The default is YES.

By the way, in case you are curious the Firewall Rules that you need to enable is the ‘Remote Shutdown’ rule.  This enables Cluster-Aware Updating to restart each node during the update process.

Okay, you are ready to go… In the Failover Cluster Manager console right-click on your cluster, and under More Actions click Cluster-Aware Updating.  In the window Failover – Cluster-Aware Updating click Apply updates to this cluster.  Follow the instructions, and your patches will begin to apply to each node in turn.  Of course, if you want to avoid the management console, all you have to do (from PowerShell) is run:

PS C:\Invoke-CauRun

However be careful… you cannot run this cmdlet from a server that is a cluster node.  So from a remote system (I use my management client that has all of my RSAT tools installed) run:

PS C:\Invoke-CauRun –ClusterName Toronto

You can watch the PowerShell progress of the update… or you can go out for ice cream.  Just make sure it doesn’t crash in the first few seconds, and it should take some time to run.

Good luck, and my the cluster force be with you!