Figure 7.11 Configuring a protected network on a virtual machine network adapter
It is important to try to provide as much resiliency as possible for network
communications, which means using NIC Teaming on the hosts as described in
Chapter 3, “Virtual Networking,” but the protected network features provide an
additional layer of resiliency to network failures.
Cluster-Aware Updating
Windows Server 2012 placed a huge focus on running the Server Core configuration
level, which reduced the amount of patching and therefore reboots required for a
system. There will still be patches that need to be installed and therefore reboots, but
the key point is to reduce (or ideally, eliminate) any impact to the virtual machines
when hosts have to be rebooted.
In a typical cluster, any impact to virtual machines is removed by live-migrating
virtual machines off of a node, patching and rebooting that node, moving the virtual
machines back, and repeating for the other nodes in the cluster. This sounds simple,
but for a 64-node cluster, this is a lot of work.
SCVMM 2012 introduced the ability to automate the entire cluster patching process
with a single click, and this capability was made a core part of Failover Clustering in
Windows Server 2012. It’s called Cluster-Aware Updating (CAU). With CAU, updates
are obtained from Microsoft Update or an on-premises Windows Server Update
Services (WSUS) implementation, and the entire cluster is patched with no impact on
the availability of virtual machines.
I walk through the entire Cluster-Aware Updating configuration and usage at the
following location:
[http://windowsitpro.com/windows-server-2012/ cluster-aware-updating-windows-](http://windowsitpro.com/windows-server-2012/ cluster-aware-updating-windows-)
server-2012
Both SCVMM cluster patching and the native Windows Server Cluster-Aware
Updating can leverage WSUS or Windows Update, but they cannot use System Center
Configuration Manager, which many organizations use as their patch solution. System
Center Configuration Manager 2016 has its own cluster awareness now, which enables
a rolling cluster patch process. Additionally, Configuration Manager includes the
ability to specify what percentage of the cluster may stay online during the operation
and additionally pre- and post-scripts can be set as each node has actions performed.
The only requirement is that all the nodes in the cluster may be in their own
Configuration Manager collection, as this is where the configuration is applied. A
change is made to the collection, specifically selecting the All Devices Are Part Of The
Same Server Cluster check box, which will enable the Settings button as part of the
collection properties. Under the Settings, there are a number of options, as shown in
Figure 7.12. Patching when applied will respect these configurations as will other
maintenance operations, giving easy ability to patch clusters.