code: def update(self):
          
          for node in self.get_all_nodes():
              try:
                  node.update_ips()
  
                  # If we previously did not have a preferred_ip or the
                  # preferred_ip is not in the current list, then try to connect
                  # to one of the node ips and update the preferred_ip.
                  if node.ips and \
                          not (node.preferred_ip and \
                                           node.preferred_ip in node.ips):
                      node.connect()
              except InstanceError as ex:
                  log.warning("Ignoring error updating information on node %s: %s",
                              node, ex)
          self.repository.save_or_update(self)
docs: Update connection information of all nodes in this cluster.
  
          It happens, for example, that public ip's are not available
          immediately, therefore calling this method might help.