Kubernetes go-client to list out pod details similar to `kubectl get pods`

5/15/2021

I'm trying to use the Kubernetes client-go to access pod details in a cluster.

I want to use it to get the details of pods running in one particular namespace, similar to kubectl get pods -n <my namespace>.

The details I want are the name, status, ready, restarts and age of the pod.

How can I get those data?

-- Navendu Pottekkat
go
kubectl
kubernetes

1 Answer

5/15/2021

So, I wrote a function that takes in a Kubernetes client (refer the client-go for details on making one) and a namespace and returns all the pods available-

func GetPods(client *meshkitkube.Client, namespace string) (*v1core.PodList, error) {
	// Create a pod interface for the given namespace
	podInterface := client.KubeClient.CoreV1().Pods(namespace)

	// List the pods in the given namespace
	podList, err := podInterface.List(context.TODO(), v1.ListOptions{})

	if err != nil {
		return nil, err
	}
	return podList, nil
}

After getting all the pods, I used a loop to run through all the pods and containers within each pod and manually got all the data I required-

// List all the pods similar to kubectl get pods -n <my namespace>
			for _, pod := range podList.Items {
				// Calculate the age of the pod
				podCreationTime := pod.GetCreationTimestamp()
				age := time.Since(podCreationTime.Time).Round(time.Second)

				// Get the status of each of the pods
				podStatus := pod.Status

				var containerRestarts int32
				var containerReady int
				var totalContainers int

				// If a pod has multiple containers, get the status from all
				for container := range pod.Spec.Containers {
					containerRestarts += podStatus.ContainerStatuses[container].RestartCount
					if podStatus.ContainerStatuses[container].Ready {
						containerReady++
					}
					totalContainers++
				}

				// Get the values from the pod status
				name := pod.GetName()
				ready := fmt.Sprintf("%v/%v", containerReady, totalContainers)
				status := fmt.Sprintf("%v", podStatus.Phase)
				restarts := fmt.Sprintf("%v", containerRestarts)
				ageS := age.String()

				// Append this to data to be printed in a table
				data = append(data, []string{name, ready, status, restarts, ageS})
			}

This will result in the exact same data as you would get when running kubectl get pods -n <my namespace>.

-- Navendu Pottekkat
Source: StackOverflow