Lab 7 - Rolling Updates¶

25 min Beginner

Problem¶

Your company's developers have just finished a new version of their Jedi-themed mobile game, and they're ready to update the backend running in your cluster. A Deployment named jedi-deployment manages the application replicas.

Update the container named jedi-ws to the new image quay.io/nginx/nginx-unprivileged:1.29 using a rolling update, and confirm the rollout succeeds. Then a teammate pushes a broken release. Roll it back.

Setup¶

oc new-project lab7

Save this manifest to jedi-deployment.yaml and apply it:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: jedi-deployment
  labels:
    app: jedi
spec:
  replicas: 3
  selector:
    matchLabels:
      app: jedi
  template:
    metadata:
      labels:
        app: jedi
    spec:
      containers:
        - name: jedi-ws
          image: quay.io/nginx/nginx-unprivileged:1.28
          ports:
            - containerPort: 8080

oc apply -f jedi-deployment.yaml
oc rollout status deployment/jedi-deployment

Tasks¶

1. Update the jedi-ws container to quay.io/nginx/nginx-unprivileged:1.29, and record why you changed it in the kubernetes.io/change-cause annotation.
2. Watch the rollout until it completes.
3. View the rollout history. You should see two revisions.
4. Deploy a broken release: update the image to quay.io/nginx/nginx-unprivileged:9.99, a tag that doesn't exist. Check the rollout status and the pods. What happens to the old pods?
5. Roll back to the working version.

Hints¶

• oc set image changes a container's image.
• oc annotate sets the change cause. The old --record flag is deprecated.
• oc rollout status, oc rollout history and oc rollout undo manage rollouts.
• Watch the pods change in real time with oc get pods -l app=jedi -w.

Verification¶

After the rollback, the Deployment runs version 1.29 with all 3 replicas available:

oc get deployment jedi-deployment -o jsonpath='{.spec.template.spec.containers[0].image}{"\n"}'
oc get deployment jedi-deployment
oc rollout history deployment/jedi-deployment

Cleanup¶

oc delete project lab7