Host names are set during setup of the server.
Host names are provided when you install a Couchbase Server node, when you add it to an existing cluster for online upgrade, or via a REST API call. If a node restarts, any host name that you established is used. A host name cannot be provided for a node that is already part of a Couchbase Server cluster.
If you attempt to specify a host name once the node is in the cluster, the server rejects the request and returns the following:
error 400 reason: unknown ["Renaming is disallowed for nodes that are already part of a cluster"]