code: def _clone_node(self, node):
          
          spec = node.gateway.spec
          spec.id = None
          self.nodemanager.group.allocate_id(spec)
          node = self.nodemanager.setup_node(spec, self.queue.put)
          self._active_nodes.add(node)
          return node
docs: Return new node based on an existing one.
  
          This is normally for when a node dies, this will copy the spec
          of the existing node and create a new one with a new id.  The
          new node will have been setup so it will start calling the
          "worker_*" hooks and do work soon.