Automation with Scripts

For script automation, you enable the True option in RequireAllNodesOnline on the Advanced Options page. Another possibility is to record scripts that are started before or after the cluster service update. In this way, you have every opportunity to engage in the update. For example, email can be sent or certain services checked automatically using the scripts. For this approach, it is best to work with PowerShell scripts. Before the update, the script is performed on each cluster node before the corresponding node is paused and updated. The script starts after the update on each cluster node after CAU has installed the updates. You can find all available options in Microsoft TechNet [1].

You do not, however, need to make advanced adjustments when setting up CAU. The wizard for enabling CAU also includes an update execution editor. With this, you can prepare the adjustments, save them as an XML file and simply use this XML file when setting up CAU (Figure 2).

Figure 2: Saving the advanced options for CAU in an XML file facilitates setting up the service.

On the next page, you can determine how the cluster service should deal with recommended updates when setting up CAU and whether they play the same role as critical updates. Here you can specifically set how updates should be installed. You will then receive a summary, and the service is finally created when you click Apply . If CAU starts an update, the service will now carry out a failover for the cluster roles. After a node has been updated, the cluster roles are moved back to the original cluster node via a failback.

Updates via PowerShell

Rather than starting the update with PowerShell, you can manage CAU with other Cmdlets (Figure 3). You can, for example, set up CAU in PowerShell with Add-CauClusterRole or export a report with Export-CauReport. You will receive all interesting Cmdlets, including their help, most quickly if you enter get-command -module ClusterAwareupdating.

Figure 3: You can also control CAU with PowerShell. To this end, you can display the individual PowerShell commands for the control and setup using get-command.

Troubleshooting the Device

If the wizard displays an error, check the rights for the computer object for the cluster update that you have created in advance. Give the cluster account full access rights to the new CAU account in the object's properties. Alternatively, you can let the wizard create the computer object itself. In this case, the wizard sets the rights. With errors, simply carry out the analysis once and make the same adjustments again.

No more errors should appear in further tests, either. You can determine which patches the service ultimately installs by sharing the patches on a WSUS server. Alternatively, you can enable the local update management on the server. You will receive the list of patches that the service installs next in the management program for CAU if you click on Preview updates for this cluster . The service uses information from Windows Update on the server. If you are working with WSUS, the WSUS updates are downloaded; if you are working with Windows Update, this function will again directly use the Windows Update function on the Internet.

To start an immediate update after setup – or later, if you currently have a fixed maintenance window, for example – click on Apply updates to this cluster . The service will begin updating the individual cluster nodes immediately. You can see the status of current installations in the CAU management tool, which you have already used to set up the service. During the update, the corresponding node is placed in maintenance state. The cluster resources, such as the VMs, are moved to other nodes. The update is started, and then the resources are transferred back again. After that, the next node is updated.