passed a file which contains RBAC roles, rolebindings, clusterroles, or
  clusterrolebindings, this command computes covers and adds the missing rules.
  The logic required to properly apply RBAC permissions is more complicated
  than a JSON merge because you have to compute logical covers operations between
  rule sets. This means that we cannot use `kubectl apply` to update RBAC roles

- **Auth**
  - [alpha] Further polishing of the Role-based access control alpha API including a default set of cluster roles. ([docs](http://kubernetes.io/docs/admin/authorization/)) ([kubernetes/features#2](https://github.com/kubernetes/enhancements/issues/2))

    it keeps your `HeldCertificate` and its chain. On the client it keeps the root certificates
    that are trusted to sign a server's certificate chain. `HandshakeCertificates` also works with
    mutual TLS where these roles are reversed.

    These classes make it possible to enable HTTPS in MockWebServer in [just a few lines of
    code][https_server_sample].

    /** The key of the message: Query */
    public static final String LABELS_Q = "{labels.q}";

    /** The key of the message: Roles */
    public static final String LABELS_ROLES = "{labels.roles}";

    /** The key of the message: Suggest Search Log */
    public static final String LABELS_SUGGEST_SEARCH_LOG = "{labels.suggestSearchLog}";

* Kubernetes now supports up to 5,000 nodes via etcd v3, which is enabled by default.
* [Role-based access control (RBAC)](https://kubernetes.io//docs/admin/authorization/rbac) has graduated to beta, and defines secure default roles for control plane, node, and controller components.
* The [`kubeadm` cluster bootstrap tool](https://kubernetes.io/docs/getting-started-guides/kubeadm/) has graduated to beta. Some highlights:

- The built-in system:csi-external-provisioner and system:csi-external-attacher cluster roles are removed as of 1.17 release ([#84282](https://github.com/kubernetes/kubernetes/pull/84282), [@tedyu](https://github.com/tedyu))

  - The built-in `system:csi-external-provisioner` and `system:csi-external-attacher` cluster roles are deprecated and will not be auto-created in a future release. CSI deployments should provide their own RBAC role definitions with required permissions. ([#69868](https://github.com/kubernetes/kubernetes/pull/69868), [@pohly]( https://github.com/pohly))...

* Fix credentials providers for docker sandbox image. ([#51870](https://github.com/kubernetes/kubernetes/pull/51870), [@feiskyer](https://github.com/feiskyer))
* Fix security holes in GCE metadata proxy. ([#51302](https://github.com/kubernetes/kubernetes/pull/51302), [@ihmccreery](https://github.com/ihmccreery))

- The `BalancedAllocation` plugin now skips all best-effort (zero-requested) pods. ([#130260](https://github.com/kubernetes/kubernetes/pull/130260), [@Bowser1704](https://github.com/Bowser1704))
- The following roles have had `Watch` added to them (prefixed with `system:controller:`):
  
  - `cronjob-controller`
  - `endpoint-controller`
  - `endpointslice-controller`
  - `endpointslicemirroring-controller`

* corrects a race condition in bootstrapping aggregated cluster roles in new HA clusters ([#63761](https://github.com/kubernetes/kubernetes/pull/63761), [@liggitt](https://github.com/liggitt))