Keeping copies of an app running
A container is a running copy of an app. When an app needs copies on several servers, Kubernetes decides where to run them. It can start replacements after a failure and gradually roll out a new version.
The servers Kubernetes manages are called a cluster. A team might tell it, “Keep three copies of our app running.” Kubernetes checks and starts a replacement if one stops.
When it helps
Kubernetes can help teams manage large or complex apps, but it takes work to set up and maintain. A smaller app may be simpler to run without it. Saying “we use Kubernetes” tells you how an app is run, not what the app does.