and on making security functions more understandable for users.

RBAC [cluster role aggregation](https://kubernetes.io/docs/reference/access-authn-authz/rbac/#aggregated-clusterroles), introduced in 1.9, graduated to stable status with no changes in 1.11, and [client-go credential plugins](https://kubernetes.io/docs/reference/access-authn-authz/authentication/#client-go-credential-plugins)  graduated to beta status, while also adding support for obtaining TLS credentials from an external...