code: func (m *Mercury) doDeleteNode(ctx context.Context, podname, nodename, endpoint string) {
  	keys := []string{
  		fmt.Sprintf(nodeInfoKey, podname, nodename),
  		fmt.Sprintf(nodePodKey, nodename),
  		fmt.Sprintf(nodeCaKey, nodename),
  		fmt.Sprintf(nodeCertKey, nodename),
  		fmt.Sprintf(nodeKeyKey, nodename),
  	}
  
  	m.BatchDelete(ctx, keys)
  	_cache.Delete(nodename)
  	log.Infof("[doDeleteNode] Node (%s, %s, %s) deleted", podname, nodename, endpoint)
  }
docs: // 因为是先写etcd的证书再拿client
  // 所以可能出现实际上node创建失败但是却写好了证书的情况
  // 所以需要删除这些留存的证书
  // 至于结果是不是成功就无所谓了