 Rolling updates. Back in the early days of DevOps, we struggled to perform what we call zero downtime deployments. Zero downtime deployments allow us to change the version of our application without disrupting users in production. The minimum requirement for zero downtime deployments is what we call blue-green deployments, at least two equal environments, one with each version, so that we can change the flow of production traffic between these environments. Luckily for us, Kubernetes allows us to perform an advanced type of blue-green deployments with zero downtime. We call it rolling updates. With this updated strategy, Kubernetes guarantees that you always have at minimum the requested amount of healthy instances running at any given moment. Let's take a look at this deployment with three instances. When we change the deployment with a rolling update strategy, Kubernetes will create another pod containing the new version of the application. Once this new pod is live and ready, Kubernetes will add it to the load balancing pool and terminate one of the older version pods. The same will happen with a second instance of the older pods. Finally, this cycle will complete with the last instance of the older pods so that all the pods in the deployment contains the new version of the application. Let's see how the rolling update happens in Prex. I already have a deployment running with three instances, and what happens when I try to change the version of my application? So I'll try to type this command and you see that as soon as I apply this command, as soon as I change the configuration of my deployment, the rolling update will happen. And I type it, you see that Kubernetes is already creating one new pod of my new version, and as soon as it's live, Kubernetes terminates one of the older versions, and it's already ready. So Kubernetes is already performing the rolling update with the three instances that I had and already have three new instances running. Thanks for watching. Don't forget to like this video and subscribe to our channel.