- IPVS: Any ipvs scheduler can now be configured. If a un-usable scheduler is configured `kube-proxy` will re-start and the logs must be checked (same as before but different log printouts). ([#114878](https://github.com/kubernetes/kubernetes/pull/114878), [@uablrek](https://github.com/uablrek))

- Fixes an issue calculating total CPU usage reported for Windows nodes ([#122999](https://github.com/kubernetes/kubernetes/pull/122999), [@marosset](https://github.com/marosset)) [SIG Node and Windows]

...

- If a bad flag is supplied to a kubectl command, only a tip to run `--help` is printed, instead of the usage menu.  Usage menu is printed upon running `kubectl command --help`. ([#82423](https://github.com/kubernetes/kubernetes/pull/82423), [@sallyom](https://github.com/sallyom))

collection algorithm. As a result, we observed an increase in memory usage for kube-apiserver in larger an heavily loaded clusters up to ~25% (with the benefit of API call latencies drop by up to 10x on 99th percentiles). If the memory increase is not acceptable for you you can mitigate by setting GOGC env variable (for our tests using GOGC=63 brings memory usage back to original value, although the exact value may depend on usage patterns on your cluster). ([#108870](https://github.com/kubernetes...

- Fixed a potential deadlock in the resource quota controller. Enabled recording partial usage info for quota objects specifying multiple resources, when only some of the resources' usage can be determined. ([#74747](https://github.com/kubernetes/kubernetes/pull/74747), [@liggitt](https://github.com/liggitt))

- Added memory tracking to scheduler performance tests to help detect memory leaks and monitored memory usage patterns while running `scheduler_perf`. ([#132910](https://github.com/kubernetes/kubernetes/pull/132910), [@utam0k](https://github.com/utam0k)) [SIG Scheduling and Testing]

secrets, a mechanism to store resource encryption keys in external Key Management Systems (KMS) was introduced. This complements the original file-based storage and allows integration with multiple KMS. A Google Cloud KMS plugin was added and will be usable once the Google side of the integration is complete.

* Websocket requests may now authenticate to the API server by passing a bearer token in a websocket subprotocol of the form `base64url.bearer.authorization.k8s.io.<base64url-encoded-bearer-token>`....

- Introduces a metric source for HPAs which allows scaling based on container resource usage. ([#90691](https://github.com/kubernetes/kubernetes/pull/90691), [@arjunrn](https://github.com/arjunrn)) [SIG API Machinery, Apps, Autoscaling and CLI]
- Kube-apiserver now deletes expired kube-apiserver Lease objects:

- kubeadm: removed preflight check for `ip`, `iptables`, `ethtool` and `tc` on Linux nodes. 
kubelet and kube-proxy will continue to report `iptables` errors if its usage is required. The tools `ip`, `ethtool` and `tc` had legacy usage in the kubelet but are no longer required. ([#129131](https://github.com/kubernetes/kubernetes/pull/129131), [@pacoxu](https://github.com/pacoxu)) [SIG Cluster Lifecycle]