Jump right into Kubernetes development with career-focused lessons and hands-on practice.

DevOps for Developers

Kubernetes is a powerful container management tool that's taking the world by storm. This detailed course will help you master it.

In this course, you'll start with the fundamentals of Kubernetes and what the main components of a cluster look like. You'll then learn how to use those components to build, test, deploy, and upgrade applications, as well as how to achieve state persistence once your application is deployed. You'll also learn how to secure your deployments and manage resources, which are crucial DevOps skills.

By the time you're done, you'll have a firm grasp on what Kubernetes is, as well as the skills to deploy your own clusters and applications with confidence.

A Practical Guide to Kubernetes

# Why should we roll back?
Discovering a critical bug is probably the most common reason for a rollback. Still, there are others. For example, we might be in a situation where Pods cannot be created. An easy to reproduce case would be an attempt to deploy an image with a tag that does not exist.
Let's update the definition of our image and deploy it again:


kubectl set image -f go-demo-2-api.yml api=vfarcic/go-demo-2:does-not-exist --record

After seeing such a message, you might be under the impression that everything is working properly. However, that output only indicates that the definition of the image used in the Deployment was successfully updated. That does not mean that the Pods behind the ReplicaSet are indeed running. For one, we can assure you that the `vfarcic/go-demo-2:does-not-exist` image does not exist.

>**Note:** Please make sure that at least 60 seconds have passed since you executed the kubectl set image command. If you’re wondering why we are waiting, the answer is in the progressDeadlineSeconds field set in the go-demo-2-api Deployment definition. That’s how much the Deployment has to wait before it deduces that it cannot progress due to a failure to run a Pod.

# Verification

Let's take a look at the ReplicaSets.

Learn how to roll back failed Deployments.

Rolling Back Failed Deployments

Why should we roll back?