kuberneteskubernetes-go-client

How can I find a Pod's Controller (Deployment/DaemonSet) using the Kubernetes go-client library?


With the following code, I'm able to fetch all the Pods running in a cluster. How can I find the Pod Controller (Deployment/DaemonSet) using the Kubernetes go-client library?

var kubeconfig *string
if home := homedir.HomeDir(); home != "" {
    kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file")
} else {
    kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
}
flag.Parse()
// use the current context in kubeconfig
config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
if err != nil {
    panic(err.Error())
}

// create the kubeClient
kubeClient, err := kubernetes.NewForConfig(config)
metricsClient, err := metricsv.NewForConfig(config)

if err != nil {
    panic(err.Error())
}

pods, err := kubeClient.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{})

if err != nil {
    panic(err.Error())
}

for _, pod := range pods.Items {
    fmt.Println(pod.Name)
    // how can I get the Pod controller? (Deployment/DaemonSet)
    // e.g. fmt.Println(pod.Controller.Name)
}

Solution

  • By following @Jonas suggestion I was able to get Pod's manager. Here's a fully working sample:

    package main
    
    import (
        "context"
        "flag"
        "fmt"
        metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
        "k8s.io/client-go/kubernetes"
        "k8s.io/client-go/tools/clientcmd"
        "k8s.io/client-go/util/homedir"
        "path/filepath"
    )
    
    func main() {
        var kubeconfig *string
        if home := homedir.HomeDir(); home != "" {
            kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file")
        } else {
            kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
        }
        flag.Parse()
        // use the current context in kubeconfig
        config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
        if err != nil {
            panic(err.Error())
        }
    
        // create the kubeClient
        kubeClient, err := kubernetes.NewForConfig(config)
    
        if err != nil {
            panic(err.Error())
        }
    
        pods, err := kubeClient.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{})
    
        if err != nil {
            panic(err.Error())
        }
    
        for _, pod := range pods.Items {
            if len(pod.OwnerReferences) == 0 {
                fmt.Printf("Pod %s has no owner", pod.Name)
                continue
            }
    
            var ownerName, ownerKind string
    
            switch pod.OwnerReferences[0].Kind {
            case "ReplicaSet":
                replica, repErr := kubeClient.AppsV1().ReplicaSets(pod.Namespace).Get(context.TODO(), pod.OwnerReferences[0].Name, metav1.GetOptions{})
                if repErr != nil {
                    panic(repErr.Error())
                }
    
                ownerName = replica.OwnerReferences[0].Name
                ownerKind = "Deployment"
            case "DaemonSet", "StatefulSet":
                ownerName = pod.OwnerReferences[0].Name
                ownerKind = pod.OwnerReferences[0].Kind
            default:
                fmt.Printf("Could not find resource manager for type %s\n", pod.OwnerReferences[0].Kind)
                continue
            }
    
            fmt.Printf("POD %s is managed by %s %s\n", pod.Name, ownerName, ownerKind)
        }
    }