In a traditional Nutanix cluster at least 3 nodes are expected to form a cluster. There is an option however to form a single-node or a two-nodes cluster for ROBO (Remote Office/Branch Office) implementations or as a backup site.
The working of the two-node cluster is different from our usual 3 or more nodes cluster. Some examples are:
-
We cannot expand a two-node cluster.
-
Node removal is not supported.
-
There is no cluster stop for 2 node cluster
So what is the graceful way to shut down and start a two-node cluster?
How to shut down a 2-node cluster:
-
Ensure that the cluster has data resiliency OK and can tolerate one node down from Prism.
-
Stop user VMs - graceful shutdown.
-
There is no cluster stop for 2 node clusters. Log in to a CVM using the nutanix account, and perform a graceful shut down of the CVM.
-
Wait for 5-10 mins, and then shut down the second CVM.
-
Shut down the hosts.
-
NOTE: The above two commands used to shutdown the CVMs are different. Take a look at the document at the end for reference.
How to start a 2-node cluster:
-
Power on the CVM from step 4 above.
-
Wait until the single node cluster is up (around 20 mins).
-
Power on the CVM from step 3 above.
-
Wait for 20 mins. (Because 2 nodes cluster became 1 node cluster, then we need to wait for 20 min to change the status to 2 node cluster back. Usually, data resiliency is not restored for extent groups immediately after cluster shutdown or node down/off. and after (usually) 2 curator scans data resiliency is back to normal)
To take a look at the commands involved to shut down the two CVMs, refer https://portal.nutanix.com/page/documents/kbs/details/?targetId=kA00e000000LL66CAG
For more information on the two-nodes cluster:
Prism Web Console Guide v5.16: Two-Node Clusters
Confused or have questions regarding the implementation or requirements/dependencies? Check out Guide for single-node and two-node clusters for any clarifications.