code: func (kubemarkController *KubemarkController) GetNodeNamesForNodeGroup(nodeGroup string) ([]string, error) {
  	selector := labels.SelectorFromSet(labels.Set{nodeGroupLabel: nodeGroup})
  	pods, err := kubemarkController.externalCluster.podLister.List(selector)
  	if err != nil {
  		return nil, err
  	}
  	result := make([]string, 0, len(pods))
  	for _, pod := range pods {
  		result = append(result, pod.ObjectMeta.Name)
  	}
  	return result, nil
  }
docs: // GetNodeNamesForNodeGroup returns list of the nodes in the node group.