'Return whether the given node is an "external" node.'

def _is_external_node(self, nodename):

    (res, nodes) = self.call_or_reconnect(self.odm.list_nodes, [nodename], 0, self.empty_dict, [dm_const.FLAG_EXTERNAL])
    self._check_result(res)
    if (len(nodes) != 1):
        msg = (_('Expected    exactly    one    node    called    "%s"') % nodename)
        LOG.error(msg)
        raise exception.VolumeDriverException(message=msg)
    (__, nodeattr) = nodes[0]
    return (getattr(nodeattr, dm_const.FLAG_EXTERNAL, dm_const.BOOL_FALSE) == dm_const.BOOL_TRUE)
