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TASK 98: Troubleshoot Issue With Pods

Requirements​

One of the junior DevOps team members was working on to deploy a stack on Kubernetes cluster. Somehow the pod is not coming up and its failing with some errors. We need to fix this as soon as possible. Please look into it.

  • There is a pod named webserver and the container under it is named as httpd-container. It is using image httpd:latest

  • There is a sidecar container as well named sidecar-container which is using ubuntu:latest image.

Look into the issue and fix it, make sure pod is in running state and you are able to access the app.

Note: The kubectl utility on jump_host has been configured to work with the kubernetes cluster.

Note

This document focuses on the implementation approach. The task statement in Requirements is preserved as the source requirement.

Prerequisites​

  • Access to the configured Kubernetes cluster from jump_host.
  • kubectl is configured and points to the correct context.
  • Use the task-specified namespace, resource names, and images exactly.

Steps​

Retrieve the running pods.

$ kubectl get pods
NAME        READY   STATUS             RESTARTS   AGE
webserver   1/2     ImagePullBackOff   0          89s

Describe the pod. From here we can see a warning that tells us about a typo error in the name of the image used. This is what we need to correct.

$ kubectl describe pods

...

Events:
  Type     Reason     Age                 From               Message
  ----     ------     ----                ----               -------
  Normal   Scheduled  119s                default-scheduler  Successfully assigned default/webserver to kodekloud-control-plane
  Normal   Pulling    117s                kubelet            Pulling image "ubuntu:latest"
  Normal   Started    111s                kubelet            Started container sidecar-container
  Normal   Pulled     111s                kubelet            Successfully pulled image "ubuntu:latest" in 5.860311432s
  Normal   Created    111s                kubelet            Created container sidecar-container
  Warning  Failed     71s (x3 over 117s)  kubelet            Failed to pull image "httpd:latests": rpc error: code = NotFound desc = failed to pull and unpack image "docker.io/library/httpd:latests": failed to resolve reference "docker.io/library/httpd:latests": docker.io/library/httpd:latests: not found
  Warning  Failed     71s (x3 over 117s)  kubelet            Error: ErrImagePull
  Normal   Pulling    71s (x3 over 118s)  kubelet            Pulling image "httpd:latests"
  Normal   BackOff    36s (x6 over 110s)  kubelet            Back-off pulling image "httpd:latests"
  Warning  Failed     36s (x6 over 110s)  kubelet            Error: ImagePullBackOff

Generate a YAML file for the pod.

kubectl get pods -o yaml > pod.yaml

Edit the spec file and ensure that the httpd container is using the correct image and tag.

    containerStatuses:
    - image: httpd:latests

Delete the resource first and apply.

kubectl delete -f pod.yaml 
kubectl apply -f pod.yaml 
$ kubectl get pods 

NAME        READY   STATUS    RESTARTS   AGE
webserver   2/2     Running   0          28s

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Verification​

  • Confirm the required pods/services/deployments/jobs are in the expected state.
  • Run kubectl get commands for the affected resource types and namespace.

Resources​