def pause(self):
        """
        Pause the VM  instance and return the info needed to restart it.
        """
        if self.instance_id is None:
            raise ValueError("Trying to stop unstarted node.")
        resp = self._cloud_provider.pause_instance(self.instance_id)
        self.preferred_ip = None
        return resp
Pause the VM  instance and return the info needed to restart it.