The WUA infrastructure can be configured to point to Microsoft Update and Windows Update or to Windows Server Update Services (WSUS) as its source of updates. By default, CAU is configured with a plug-in that uses the Windows Update Agent (WUA) utility APIs on the cluster nodes.
The WUA infrastructure can be configured to point to Microsoft Update and Windows Update or to a local Windows Server Update Services (WSUS) server as its source of updates. Limited distribution release (LDR) updates, also called hotfixes, are not published through Microsoft Update or Windows Update, so they cannot be downloaded by the Windows Update Agent (WUA) plug-in that CAU uses by default.
You can start an Updating run through the Cluster-Aware Updating window or by using the Invoke-Cau Run Power Shell cmdlet.
Remote-updating is the default updating mode for CAU.
You can also start a Self-Updating Run on demand at any time.
To enable self-updating mode, you must add the CAU clustered role to the cluster.
However, performing software updates on a server (with the associated potential restarts) while a server backup is in progress is not an IT best practice.Be aware that CAU relies only on clustering APIs to determine resource failovers and failbacks; thus, CAU is unaware of the server backup status.CAU is a tool that coordinates software updates on a cluster node, and Configuration Manager also performs server software updates.Specifically, CAU orchestration ensures that suspending each cluster node waits for the underlying clustered storage space to be healthy. CAU coordinates the cluster updating operation only from computers running Windows Server 2016, Windows Server 2012 R2, Windows Server 2012, Windows 10, Windows 8.1, or Windows 8.The failover cluster being updated must run Windows Server 2016, Windows Server 2012 R2, or Windows Server 2012. CAU is agnostic to the type of the clustered application.Thus in the absence of unplanned failovers and preferred owner settings, the distribution of clustered roles should remain unchanged.