- kube-controller-manager currently needs a writable `--cert-dir` (default...

- Limits lease to have 1000 maximum attached objects. ([#98257](https://github.com/kubernetes/kubernetes/pull/98257), [@lingsamuel](https://github.com/lingsamuel))

* Fixed dynamic provisioning of GCE PDs to round to the next GB (base 1000) instead of GiB (base 1024). ([#56600](https://github.com/kubernetes/kubernetes/pull/56600), [@edisonxiang](https://github.com/edisonxiang))

        *   HostPorts are not supported.
*   An IPv6 network mask for pod or cluster cidr network must be /66 or longer. For example: 2001:db1::/66, 2001:dead:beef::/76, 2001:cafe::/118 are supported. 2001:db1::/64 is not supported

## Changelog since v1.18.5

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

 - CVE-2020-8559 (Medium): Privilege escalation from compromised node to cluster. See https://github.com/kubernetes/kubernetes/issues/92914 for more details.

* Introduced `--http2-max-streams-per-connection` command line flag on api-servers and set default to 1000 for aggregated API servers. ([#60054](https://github.com/kubernetes/kubernetes/pull/60054), [@MikeSpreitzer](https://github.com/MikeSpreitzer))

## Changelog since v1.17.8

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

 - CVE-2020-8559 (Medium): Privilege escalation from compromised node to cluster. See https://github.com/kubernetes/kubernetes/issues/92914 for more details.

If a REST API reaches the end of that nine-month countdown, then the next Kubernetes release will deprecate that API version. More information can be found on [the Kubernetes Blog](https://kubernetes.io/blog/2020/08/21/moving-forward-from-beta/).

### Expanded CLI support for debugging workloads and nodes

  check for stale rules on every sync. (In smaller clusters, it will still
  remove unused rules immediately once they are no longer used.)

  (The threshold for "large" used here is currently "1000 endpoints" but
  this is subject to change.) ([#110334](https://github.com/kubernetes/kubernetes/pull/110334), [@danwinship](https://github.com/danwinship))

- Alpha swap support can now be enabled on Kubernetes nodes with the `NodeSwapEnabled` feature flag. See [KEP-2400](https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/2400-node-swap/README.md#design-details) for details. ([#102823](https://github.com/kubernetes/kubernetes/pull/102823), [@ehashman](https://github.com/ehashman))