Sunday, August 21, 2016

VSAN : Migrate VSAN cluster from vSS to vDS

How to migrate a VSAN cluster from vSS to vDS

I am sure there some of you that is currently a VSAN cluster in some shape or form either in POC, Development or Production environment.  It provides a cost effective solution that is great for remote offices or even management clusters and can be implemented and managed very easily but as the saying goes nothing ever come easy and you have to work for it.  The same goes here and there are a lot of prerequisites for a VSAN environment that is crucial for implementing a healthy system that performs to its full potential.  I will not go into much detail here and feel free to contact us if any services are required.   
One of the recommendations for VSAN is to use a vDS and your VSAN license actually includes the ability to use vDS which allows you as our customer to take advantage of simplified network management regardless of the underlying vSphere edition.

If you upgrade from vSS to vDS the steps are a bit different that your normal migration.  I recommend you put the host into maintenance mode with ensure accessibility.  Verify the uplink used for VSAN VMkernel and use the manage physical network adapter to remove the vmnic from vSS and to add it to vDS. Now migrate the VMkernel to the VDS.  If you review the VSAN health the network will show failed.
To verify multicast network traffic is flowing from you host use the following command on the ESXi host using bash shell:
#tcpdump-uw -i vmk2 -n -s0 -t -c 20 udp port 23451 or ump port 12345
To review your multicast network settings
#esxcli vsan network list
Ruby vSphere Console (RVC) is also a great tool to have in your arsenal for managing VSAN and following command can be used to review the VSAN state:
vsan.check_state <cluster>
To re-establish the network connection you can use the following command:
vsan.reapply_vsan_vmknic_config <host>

Rerun the VSAN health test and verify Network shows passed.

Now that the VSAN network is up and running you can migrate the rest of VMkernels.