Deployment Strategies: Rolling Updates, Blue-Green, and Canary

You push a new container image. Kubernetes creates new pods, tears down old ones, and eventually everything is running the latest version. That's the default behavior, and most teams never question it.

But "the default" is a specific strategy with specific trade-offs. A rolling update replaces pods incrementally. That works until you need instant rollback, or until you need to test a new version with 5% of traffic before going all-in. At that point, you need a different strategy. Kubernetes won't hand you one out of the box.