🔄 Revert Deployment to Previous Version in Kubernetes (Step-by-Step Guide)

Even with proper testing, bugs can sometimes slip into production. Kubernetes makes it easy to rollback a Deployment to a previous stable version using its built-in rollout history.

In this guide, we’ll walk through how the Nautilus DevOps team can revert an application to its previous version after detecting an issue in the latest release.

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🧠 Scenario Overview

• A new version of an application was deployed earlier today

• Customers reported a bug in the latest release

• The application is managed by a Deployment named nginx-deployment

• Goal: Rollback the Deployment to the previous revision and ensure all Pods are healthy

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📌 What Is a Deployment Rollback?

A rollback:

• Restores the Deployment to a previous revision

• Recreates Pods using the older configuration/image

• Helps recover quickly from faulty releases

• Minimizes downtime and risk

Kubernetes automatically maintains a revision history for Deployments.

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🧩 Step 1: Roll Back to the Previous Revision

Use the following command to revert the Deployment to its last stable version:

kubectl rollout undo deployment nginx-deployment

✅ Expected Output

deployment.apps/nginx-deployment rolled back

Kubernetes will now:

• Terminate Pods running the faulty version

• Recreate Pods using the previous revision

• Maintain availability during the rollback

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🔎 Step 2: Monitor the Rollback Status

Check the rollout status to ensure the rollback completes successfully:

kubectl rollout status deployment nginx-deployment

🟢 Sample Output

deployment "nginx-deployment" successfully rolled out

⏳ If the rollback is still in progress, Kubernetes will display live status updates.

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📦 Step 3: Verify the Pods

Confirm that all Pods are running and healthy:

kubectl get pods

🟢 Sample Output

NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-5d9f7c6f8b-x2kqj   1/1     Running   0          30s
nginx-deployment-5d9f7c6f8b-p9wld   1/1     Running   0          28s

All Pods should be in the Running state with READY = 1/1.

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🧾 Optional: Check Rollout History

To view the revision history of the Deployment:

kubectl rollout history deployment nginx-deployment

This helps you:

• Identify previous versions

• Roll back to a specific revision if needed

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🛠️ Roll Back to a Specific Revision (Optional)

If you want to roll back to a specific revision number:

kubectl rollout undo deployment nginx-deployment --to-revision=1

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🎯 Conclusion

In this guide, you learned how to:

• Roll back a Kubernetes Deployment to a previous version

• Monitor rollback progress

• Verify application health after rollback

• Inspect Deployment rollout history

Rollback is a critical production skill that allows teams to respond quickly to failures and maintain system stability.

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🚀 Next Steps

Great follow-up topics for your next Kubernetes blog:

• Rolling Updates vs Rollbacks

• Canary deployments in Kubernetes

• Blue-Green deployment strategies

• Managing Deployment revision history

• Zero-downtime release strategies