code: def pause(self):
          
          log.info("Pausing cluster `%s` ...", self.name)
          failed = self._pause_all_nodes()
          if os.path.exists(self.known_hosts_file):
              os.remove(self.known_hosts_file)
          self.repository.save_or_update(self)
          if failed:
              log.warning(
                      "Not all cluster nodes have been successfully "
                      "stopped.  Some nodes may still be running - "
                      "check error messages above and consider "
                      "re-running `elasticluster pause %s` if "
                      "necessary.", self.name)
docs: Pause all VMs in this cluster and store data so that they
          can be restarted later.