* The `rbac.authorization.k8s.io/v1beta1` API has been promoted to `rbac.authorization.k8s.io/v1` with no changes. ([#49642](https://github.com/kubernetes/kubernetes/pull/49642), [@liggitt](https://github.com/liggitt))
    * The `rbac.authorization.k8s.io/v1alpha1` version is deprecated and will be removed in a future release.

- Added --authorization-always-allow-paths to components doing delegated authorization to exclude certain HTTP paths like /healthz from authorization. ([#67543](https://github.com/kubernetes/kubernetes/pull/67543), [@sttts](https://github.com/sttts))

- All resources within the `rbac.authorization.k8s.io/v1alpha1` and `rbac.authorization.k8s.io/v1beta1` API groups are deprecated in favor of `rbac.authorization.k8s.io/v1`, and will no longer be served in v1.20. ([#84758](https://github.com/kubernetes/kubernetes/pull/84758), [@liggitt](https://github.com/liggitt))

- `kube-apiserver` added two new metrics `authorization_attempts_total` and `authorization_duration_seconds`
  that allow users to monitor requests to authorization webhooks, split by result. ([#117211](https://github.com/kubernetes/kubernetes/pull/117211), [@HirazawaUi](https://github.com/HirazawaUi))

Kubernetes 1.11 also makes it easier to see what's happening, as audit events can now be annotated with information about how an API request was handled:
  * Authorization sets `authorization.k8s.io/decision` and `authorization.k8s.io/reason` annotations with the authorization decision ("allow" or "forbid") and a human-readable description of why the decision was made (for example, RBAC includes the name of the role/binding/subject which allowed a request).

- The following features...

  - The `Node` authorization mode no longer allows kubelets to delete their Node API objects (prior to 1.11, in rare circumstances related to cloudprovider node ID changes, kubelets would attempt to delete/recreate their Node object at startup) ([#71021](https://github.co...

### Auth

- The default delegating authorization options now allow unauthenticated access to healthz, readyz, and livez.  A system:masters user connecting to an authz delegator will not perform an authz check. ([#98325](https://github.com/kubernetes/kubernetes/pull/98325), [@deads2k](https:/...

- Added authorization check support to the CEL expressions of ValidatingAdmissionPolicy via a `authorizer`