k8s is actually a story of the triumph of interfaces. CoreOS may have stumbled on to it first, but k8s's real power is in the Operator (CRD + Controller) paradi

k8s is actually a story of the triumph of interfaces. CoreOS may have stumbled on to it first, but k8s's real power is in the Operator (CRD + Controller) paradigm. Operators are essentially interfaces-as-YAML + implementations-as-connected-services. So much of the successful simplification of k8s today is due to being able to move complexity out of tree and delegate functionality to external pieces. The sort of interface-interface that CRDs represent is doing a lot of heavy lifting in being able to simplify k8s.