Kubernetes API - gets Pods on specific nodes

Question

Looking at http://kubernetes.io/docs/user-guide/labels/#selecting-sets-of-nodes it looks to be possible to select a certain range of pods based on labels. But in my case I w

Answer 1

I've gone through the same process with the Go Client and it uncovers a few shortcuts the CLI is taking.

func doNodesHavePods(clientset *kubernetes.Clientset) error {
    nodeLabelSelector := "nodelabel=interesting_nodes"
    nodes, err := clientset.CoreV1().Nodes().List(metav1.ListOptions{LabelSelector: nodeLabelSelector})

    if err != nil {
        return err
    }

    nodeNames := []string{}
    for _, node := range nodes.Items {
        nodeNames = append(nodeNames, node.Name)
    }
    // --all-namespaces -> listing and looping on namespaces
    namespaces, err := clientset.CoreV1().Namespaces().List(metav1.ListOptions{})

    if err != nil {
        return err
    }
    for _, namespace := range namespaces.Items {
        for _, name := range nodeNames {
            // pods need a namespace to be listed.
            pods, err := clientset.CoreV1().Pods(namespace.Name).List(metav1.ListOptions{FieldSelector: "spec.nodeName=" + name})
            if err != nil {
                println("%v", err)
            }
            for _, pod := range pods.Items {
                fmt.Println(pod.Namespace, pod.Name)
            }
        }
    }
    return nil
}

I've started to find that a lot of the questions I need to ask are becoming too complex for the CLI which is a great workhorse, but learning to use the Go Client can help you get the first answer you're looking for, but also dig deeper into questions that those answers raise.