code: func (os *OpenStack) GetNodeNameByID(instanceID string) (types.NodeName, error) {
  	client, err := os.NewComputeV2()
  	var nodeName types.NodeName
  	if err != nil {
  		return nodeName, err
  	}
  
  	server, err := servers.Get(client, instanceID).Extract()
  	if err != nil {
  		return nodeName, err
  	}
  	nodeName = mapServerToNodeName(server)
  	return nodeName, nil
  }
docs: // GetNodeNameByID maps instanceid to types.NodeName