Why do we use rolling updates and rollbacks in Kubernetes?

Rolling updates are the best way to upgrade apps managed by Kubernetes. They avoid headaches for both users and website owners. The biggest benefit is zero downtime during the upgrade. The site or app remains available throughout the process. Containers with the old software version keep running until replaced gradually by new containers. So users enjoy continuous access.

This compares extremely well to regular software updates. Those require completely stopping the old app, installing the new version, and restarting it. That whole process means taking the app offline for minutes or even hours in some cases. Customers get annoyed by downtime interrupting their work or entertainment!

Rolling updates minimize downtime:

Rolling updates also slowly phase in the changes behind the scenes. For example, a website redesign goes live 10 or 20 percent at a time across the container cluster. So if bugs pop up with the new version, only some users are impacted before fixes can be made. An all-at-once regular update could cripple the whole website if not tested enough. So when is this clever Kubernetes approach especially useful? Continuous deployment and integration workflows rely on frequent incremental improvements to apps. For example, companies like Amazon and Netflix update their apps even multiple times per day! Zero downtime is required to avoid losing sales or customers along the way.

Continuous deployment, no downtime:

Apps demanding extremely high reliability and uptime also benefit. Things like banking systems, cloud infrastructures, communication platforms. Rolling updates let them evolve without service interruptions during business hours or critical loads. In summary, rolling updates minimize headaches both for those running and using containerized apps. So why ever take things offline to upgrade when you don’t have to?

Many websites and apps now run on clusters of computers called containers. Containers let apps run smoothly as groups work on updating and improving the software behind the apps. A system called Kubernetes helps manage and update all those containerized apps. Sometimes app updates go wrong or cause problems for users. Kubernetes has clever ways to update apps that avoid issues.

The main method is called a rolling update. This slowly switches the software behind the scenes from an old version to a new one. A few containers at a time are updated to the new software. Kubernetes checks that each small batch works fine before updating more. This means no downtime for users! Another useful capability is rollbacks. If a new software version causes glitches, Kubernetes can automatically revert to the previous stable version. There is no need for websites to crash or stay broken!