HowTo configure the CAU Cluster Role

Windows Server 2012 (currently only available as a preview version) now supports “Cluster Aware Updating” (CAU). This means you only need to click on Update Cluster and the CAU-Tools takes care of updating the cluster including failing-over the services, installing updates and rebooting the servers.

Feature Description:

  • Puts each node of the cluster into node maintenance mode
  • Moves the clustered roles off the node
  • Installs the updates and any dependent updates
  • Performs a restart if necessary
  • Brings the node out of maintenance mode
  • Restores the clustered roles on the node
  • Moves to update the next node


This Feature can be used in two ways: Self Updating Mode and Remote Updating Mode. All the functionality is available together with the Windows RSAT Feature “Failover Clustering Tools”.

Self-updating mode
If you enable self-updating, it will be configured as additional Workload on the Failover Cluster and starts based on a configured schedule.

Create an additional Computer account
Before you start, you must create an additional computer account for the Cluster, lets call it “SERVER01CAU” here. This account is needed for CAU to run as Workload on the Cluster. Edit the security settings in Active Directory on this account and add the Cluster’s own Computer account as User with full rights. In my case it’s “SERVER01Win$”.

This isn’t documented yet anywhere on Microsoft’s Technet pages, but if you don’t create the AD Computer account you’ll get error messages and the configuration fails. In the Cluster’s Eventlog, you’ll then see error messages telling you that the cluster haven’t had enough rights to create an AD account.

Configuration using the GUI
To configure self-updating use the “Cluster-Aware Updating” from the Administrative Tools. If you have installed server core (recommended) you must use the PowerShell command, the GUI is not available.

Picture(1) – Cluster-Aware Updating GUI
Picture(2) – CAU Configure cluster self-updating options

Configuration using PowerShell Command
To configure self-updating using PowerShell, you can use the “Set-CauClusterRole” cmdlet. Hint: You can use another server / workstation with RSAT installed to generate the PowerShell command if you use the GUI Assistant. The PowerShell command that will configure the Cluster is displayed in the details before you click Finish.

Set-CauClusterRole -ClusterName SERVER01Win-Force -CauPluginName WindowsUpdateAgent -MaxRetriesPerNode 3 -CauPluginArguments @{ ‘IncludeRecommendedUpdates’ = ‘False’ } -StartDate “06/11/2012 03:00:00” -DaysOfWeek 127 -IntervalWeeks 1;Enable-CauClusterRole -ClusterName SERVER01Win -Force -ConfigurationName SERVER01CAU;

When you let Windows configure self-updating using both ways, GUI and PowerShell, this will install a workload on the destination Failover Cluster and runs based on the schedule provided at configuration time.

The workload is not visible on the Failover Cluster GUI, but you can display it using the following command:

Get-ClusterResource -Cluster SERVER01Win

You get a list of all resources on your Cluster where the resource “ClusterAwareUpdatingResource” is the new self-updating Workload.

PS > Get-ClusterResource -Cluster SERVER01Win | ? {$_.ResourceType -like “*Updating*”} | Ft -Auto

Name                State  OwnerGroup  ResourceType
—-                —–  ———-  ————
CAUSERVEfw8Resource Online CAUSERVEfw8 ClusterAwareUpdatingResource

Remote-updating mode
This mode does not install anything additional on the Cluster or the nodes, but needs another Server running to issue the commands or run the PowerShell scripts that trigger the Update mechanism. This third Machine is called “Update Coordinator” and only needs the CAU Tools installed (RSAT Failover Clustering Tools).

You can either use the same GUI as you see on Screenshot (2) to Apply updates and let the computer you’re using coordinate the Update installation process. Or you use the following PowerShell cmdlet:

Invoke-CauRun -ClusterName SERVER01Win -Force -CauPluginName WindowsUpdateAgent -MaxRetriesPerNode 3 -CauPluginArguments @{ ‘IncludeRecommendedUpdates’ = ‘False’ };

So because this can also be invoked using a script during the night, you have the option if you prefer to install the CAU using self-updating Cluster Feature


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