Why is a kubernetes pod with a simple hello-world image getting a CrashLoopBackOff message

ghz 1years ago ⋅ 7765 views

Question

pod.yml

apiVersion: v1
kind: Pod
metadata:
    name: hello-pod
    labels:
        zone: prod
        version: v1
spec:
    containers:
    - name: hello-ctr
      image: hello-world:latest
      ports:
      - containerPort: 8080

kubectl create -f pod.yml

kubectl get pods
NAME        READY     STATUS             RESTARTS   AGE
hello-pod   0/1       CrashLoopBackOff   5          5m

Why CrashLoopBackOff?

Answer

In this case the expected behavior is correct. The hello-world container is meant to print some messages and then exit after completion. So this is why you are getting CrashLoopBackOff -

Kubernetes runs a pod - the container inside runs the expected commands and then exits.

Suddenly there is nothing running underneath - so the pod is ran again -> same thing happens and the number of restarts grows.

You can see that inkubectl describe pod where Terminated state is visible and the Reason for it is status Completed. If you would choose a container image which does not exit after completion the pod would be in running state.

#kubernetes