Operators: Pattern, Installation, and Lifecycle

A CRD gives you a new resource type in the Kubernetes API. You can create instances of it, list them with kubectl, store them in etcd. But a CRD on its own does nothing. It is a schema with no behavior. The moment you pair that CRD with a controller that watches its instances and reconciles the cluster toward the desired state, you have an operator.

The operator pattern is how most production add-ons work: cert-manager watches Certificate resources and provisions TLS certificates. The prometheus-operator watches Prometheus resources and deploys configured Prometheus instances. The CKA exam now explicitly tests your ability to install operators, interact with their custom resources, and reason about their behavior. This lesson covers the pattern itself, three installation methods you will encounter in practice, and the lifecycle concerns that matter on day two.