code: public static UUID setLocalHostId(UUID hostId)
      {
          String req = "INSERT INTO system.%s (key, host_id) VALUES ('%s', ?)";
          executeInternal(String.format(req, LOCAL_CF, LOCAL_KEY), hostId);
          return hostId;
      }
docs: Sets the local host ID explicitly.  Should only be called outside of SystemTable when replacing a node.