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Rollback

Learn to undo with kubectl rollout undo.

Rollback

A Deployment keeps old ReplicaSets (10 by default, revisionHistoryLimit); thanks to this, rolling back takes seconds. The history is seen with rollout history:

$ kubectl rollout history deployment/web
REVISION  CHANGE-CAUSE
1         <none>
2         nginx 1.27.3
3         nginx 1.28 deneme
$ kubectl rollout undo deployment/web                   # to the previous version
$ kubectl rollout undo deployment/web --to-revision=1  # to a specific version

Pausing and resuming

To make several changes (image, resources, environment variables) in a single rollout, the deployment is paused; changes accumulate and are applied at once when resumed. To redo a rollout from the start, restart is used (e.g. when a ConfigMap changed):

kubectl rollout pause deployment/web
kubectl set image deployment/web nginx=nginx:1.27.3
kubectl set resources deployment/web -c nginx --limits=memory=256Mi
kubectl rollout resume deployment/web
kubectl rollout restart deployment/web

Practice Roll back a bad version

Write three commands: show the rollout history of the web deployment; roll back to revision 2; wait for the rollout to finish.

Starter code

terminal
# buraya yaz

Sample solution

terminal
kubectl rollout history deployment/web
kubectl rollout undo deployment/web --to-revision=2
kubectl rollout status deployment/web

Expected output

REVISION  CHANGE-CAUSE
1         <none>
2         nginx 1.27.3
3         nginx 1.28 deneme
deployment.apps/web rolled back
deployment "web" successfully rolled out

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What happens in the history after kubectl rollout undo deployment/web?

  • The last revision is deleted and the number goes back
  • The history is cleared
  • Nothing changes
  • The previous version's template comes back with a new revision number Correct answer

Explanation: A rollback is also a rollout.

2 Go back to a specific revision.

Question 
kubectl rollout undo deployment/web ____=1
Answer 
kubectl rollout undo deployment/web --to-revision=1

Explanation: --to-revision takes the number from the history.

3 Match.

Term Meaning
rollout history Revision history
rollout undo Roll back
rollout pause/resume Batch changes
rollout restart Recreate the pods

All lessons in Intermediate

1 What is Kubernetes?

  1. What is Kubernetes?
  2. Why Kubernetes?
  3. Cluster architecture
  4. Control plane
  5. Worker node
  6. Summary - What is Kubernetes

2 Minikube

  1. What is Minikube?
  2. Installing Minikube
  3. minikube start
  4. minikube status
  5. minikube dashboard
  6. Summary - Minikube

3 kubectl basics

  1. What is kubectl?
  2. kubectl get
  3. kubectl describe
  4. kubectl apply
  5. kubectl delete
  6. Summary - kubectl

4 Pod

  1. What is a Pod?
  2. Pod YAML
  3. Creating a Pod
  4. Pod status
  5. Multi-container Pod
  6. Summary - Pod

5 Deployment

  1. What is a Deployment?
  2. Deployment YAML
  3. Replica count
  4. Rolling update
  5. Rollback
  6. Summary - Deployment

6 ReplicaSet

  1. What is a ReplicaSet?
  2. ReplicaSet YAML
  3. ReplicaSet selector
  4. Scaling
  5. Self-healing
  6. Summary - ReplicaSet

7 Service

  1. What is a Service?
  2. ClusterIP
  3. NodePort
  4. LoadBalancer
  5. Service selector
  6. Summary - Service

8 ConfigMap

  1. What is a ConfigMap?
  2. ConfigMap YAML
  3. Environment variable
  4. Mounting as a volume
  5. kubectl create configmap
  6. Summary - ConfigMap

9 Secret

  1. What is a Secret?
  2. Secret types
  3. Secret YAML
  4. Mounting a Secret
  5. kubectl create secret
  6. Summary - Secret

10 Namespace

  1. What is a Namespace?
  2. kubectl get namespaces
  3. Creating a Namespace
  4. The -n flag
  5. Default Namespace
  6. Summary - Namespace

11 Labels and selectors

  1. What is a label?
  2. Adding labels
  3. Label selector
  4. kubectl get -l
  5. Equality and set selectors
  6. Summary - Labels

12 Project: Multi-tier app

  1. Project design
  2. Database Deployment
  3. Web Deployment
  4. ConfigMap and Secret
  5. Putting it together - multi-tier

13 Troubleshooting

  1. kubectl logs
  2. kubectl exec
  3. kubectl describe pod
  4. CrashLoopBackOff
  5. Pending Pod
  6. Summary - Troubleshooting

14 Intermediate final

  1. Challenge - Pod YAML
  2. Challenge - Deployment
  3. Challenge - Service
  4. Challenge - ConfigMap
  5. Challenge - Intermediate project