Now that, we have completed the ESX and witness hosts installations, its time to test the network connectivity and also here is where we do the Witness Traffic Separation. To begin with, enable SSH on all the ESXi hosts and connect to them with putty.
Ensure the below ports are open bidirectional before proceeding further.
Use esxcli vsan network list to display the current vsan setup. As you can see below, we have one VMkernerl interface on each host configured to handle VSAN Traffic as we saw earlier.
Below is the vsan network config on the Witness host.
The next step would be to configure a VMkernel interface on each ESXi host to use for Witness Traffic. This can be only done using the command line. So on each host run the below command. Any VMkernel interface other than one configured with VSAN Traffic can be used for this purpose. You can use Management Network VMkernel interface as well.
esxcli vsan network ipv4 add -i vmkX -T=witness
In my case, i am using vmk1 on esx1 and vmk2 on esx2 host, both are also handling the vMotion Traffic. Now check the network configuration using esxcli vsan network list and see that we now see the witness traffic also in the list.
After all the hardwork, now its time to check the connectivity between data nodes and also the connectivity from data nodes to witness. Use vmkping to exclusively test the connectivity from VMkernel interfaces we configured.
vmkping -I vmkX <target IP>
Also test the connectivity to data nodes from Witness host. You can see that all the networking is fine in my case. Since i have all the hosts including Witness in the same subnet, i dint have to add static routes to the hosts to reach VSAN Traffic. To add static routes to the hosts use the below. In 2 Node Direct node, you would need to add static route to Witness host on data nodes and 2 routes on Witness host to reach data nodes.
esxcli network ip route ipv4 add –n <remote network> -g <gateway to use>
Once the network connectivity is verified, you are all set to enable VSAN on the cluster.
Hope this was informative. Thanks!