This lab is designed to help prepare for the kinds of tasks and scenarios encountered during the Certified Kubernetes Application Developer (CKAD) exam.
Here, there is an opportunity to practice debugging applications in Kubernetes. We will locate a problem in the Kubernetes cluster and fix it.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Identify the broken object and save its name and summary data
Become the
rootuser so that we can write to the file:sudo -iDescribe the broken service:
kubectl describe service oauth-provider -n gemNote that the service’s selector selects pods with the label
role: oauth.Get a list of pods with labels in order to locate the pod(s) selected by the service:
kubectl get pods --all-namespaces --show-labelsNote that the pod called
bowlinehas therole: oauthlabel.Save the name of the broken pod:
vi /usr/ckad/broken-object-name.txtPut the word
bowlinein there.Save the JSON summary data for the broken pod to the specified file:
kubectl get pod bowline -n gem -o json > /usr/ckad/broken-object.json- Fix the problem
Examine the broken pod more closely:
kubectl describe pod bowline -n gemBased on the event log and pod status, it appears something may be wrong with the pod image. Look at the pod’s container image, which appears to be misspelled. Edit the pod:
kubectl edit pod bowline -n gemFix the image name by changing it to
nginx:1.15.9.Verify that the pod is now working:
kubectl get pod bowline -n gemTest the broken service to make sure it is working:
curl localhost:30080
