Using Rolling Updates in Kubernetes

 

What is a Rolling Update?

A Rolling Update is a Kubernetes deployment strategy that updates an application without downtime by gradually replacing old Pods with new Pods.

Why Use Rolling Updates?

No downtime during application updates.

Users can continue accessing the application.

Safer deployment process.

Easy rollback if something goes wrong.

Example:  Suppose you have a Pods running version pod-v1 You update the image to pod-v2, Kubernetes performs the update gradually, Users can access the application throughout the update process.

Perform a Rolling Update

Update the image - kubectl set image deployment/nginx-deployment nginx=nginx:latest

Check update status: - kubectl rollout status deployment/nginx-deployment

View Rollout History

kubectl rollout history deployment nginx-deployment

Rollback to Previous Version

If the new version has issues, then Kubernetes restores the previous working version.

kubectl rollout undo deployment nginx-deployment

Verify Deployment

kubectl get deployments

kubectl get pods

How It Works

Deployment

     |

Rolling Update

     |

Old Pods ---> New Pods

(v1)          (v2)

Kubernetes removes old Pods and creates new Pods gradually until all Pods run the new version.