Operators

The CRD applies cleanly. The Custom Resource is in the cluster. You run kubectl get myresource and it's there — status Active, no errors. But nothing else is happening. No pods, no services, no state changes. You have the data model. Nobody's home to act on it.

That gap is what operators fill. A CRD defines the schema; an operator is the controller that watches those resources and does the work. Together they let you encode operational knowledge into the Kubernetes control loop itself: how to deploy a database cluster, rotate a TLS certificate, configure a monitoring stack.