ltcluster witness register — add a witness node's information to the ltcluster metadata
      ltcluster witness register adds a witness server's node
      record to the ltcluster metadata, and if necessary initialises the witness
      node by installing the ltcluster extension and copying the ltcluster metadata
      to the witness server. This command needs to be executed to enable
      use of the witness server with ltclusterd.
    
      When executing ltcluster witness register, database connection
      information for the cluster primary server must also be provided.
    
      In most cases it's only necessary to provide the primary's hostname with
      the -h/--host option; ltcluster will
      automatically use the user and dbname
      values defined in the conninfo string defined in the
      witness node's ltcluster.conf, unless these are explicitly
      provided as command line options.
    
        The primary server must be registered with ltcluster primary register before the witness
        server can be registered.
      
      Execute with the --dry-run option to check what would happen
      without actually registering the witness server.
    
    $ ltcluster -f /etc/ltcluster.conf witness register -h node1
    INFO: connecting to witness node "node3" (ID: 3)
    INFO: connecting to primary node
    NOTICE: attempting to install extension "ltcluster"
    NOTICE: "ltcluster" extension successfully installed
    INFO: witness registration complete
    NOTICE: witness node "node3" (ID: 3) successfully registered
      
--dry-runCheck prerequisites but don't actually register the witness
-F/--forceOverwrite an existing node record
      A witness_register event notification will be generated.