Cluster: Best Practices
While technically we consider one node as a cluster, obviously it is not the recommended configuration.
A two nodes cluster is also not recommended, since the cluster must have a majority of nodes to operate,
and in this case, if one of the nodes is down or partitioned, no raft command will be committed, although any database on the surviving node will still be responsive to the user.
So the best practice is to have any odd number of nodes equal or greater than 3.