What is interesting here is that the cluster service traffic essentially flows through the
networking stack twice, once through the NetFT bound stack and then through the
stack bound to the network adapter being used. In Windows Server 2012, a new
component was introduced, the NetFT Virtual Adapter Performance Filter that was
automatically bound to physical network adapters. When it sees any cluster traffic on
the physical network adapter, it sends it to the NetFT adapter directly, bypassing the
redirection through the physical network stack. This sounds good, but if you also have
a guest cluster running on virtual machines within the Hyper-V host cluster and guest
VMs are running on different nodes in the cluster, the performance filter would grab
not only the host cluster communications but also the guest cluster communications,
which means that the communication would never reach the virtual machines and
therefore break clustering. To resolve this problem, the Microsoft Failover Cluster
Virtual Adapter Performance Filter would need to be disabled in Windows Server
2012, which is why it’s disabled by default in Windows Server 2012 R2 and above.
No manual firewall configurations are required when using clustering. When the
Failover Clustering feature is installed, built-in inbound and outbound rules are
automatically enabled for the inbox Windows Firewall. If you are using a third-party
firewall solution, however, it’s important that you enable the required firewall
exceptions. The best way to do this is to look at all of the Failover Cluster firewall
exceptions and emulate them in whatever firewall product you are using.
Performing Cluster Validation
Now that you understand the importance of the cluster network and communications,
it’s time to get a cluster up-and-running, which is a simple process. The cluster
validation process performs detailed tests of all the major areas related to the cluster
configuration, such as network, storage, OS tests, and tests specific to Hyper-V in
order to ensure that the cluster will be workable and supported by Microsoft.
As previously mentioned, the cluster validation should be performed prior to creating
a cluster and anytime you make a major change to the cluster, such as adding a new
node to the cluster, adding a new network, or adding new types of storage.
Additionally, the cluster validation tool is useful to run if you are experiencing
problems with the cluster; it allows specific groups of tests to be run instead of all
tests.
Provided the Failover Clustering feature is installed on the cluster nodes to perform a
validation, follow these steps:
1 . Start Failover Cluster Manager.
2 . The root Failover Cluster Manager navigation node will be selected, which in the
Management section has a Validate Configuration action, as shown in Figure 7.21,
that you should click. If you wish to validate an existing cluster, select the cluster
in Failover Cluster Manager and then click its Validate Cluster action.
3 . Click Next on the introduction screen of the Validate a Configuration Wizard.