- DRA: scheduling pods is up to 16x faster, depending on the scenario. Scheduling throughput depends a lot on cluster utilization. It is higher for lightly loaded clusters with free resources and gets lower when the cluster utilization increases. ([#127277](https://github.com/kubernetes/kubernetes/pull/127277), [@pohly](https://github.com/pohly)) [SIG API Machinery, Apps, Architecture, Auth, Etcd, Instrumentation, Node, Scheduling...

- Correct a reference to a not/no longer used kustomize subcommand in the documentation ([#82535](https://github.com/kubernetes/kubernetes/pull/82535), [@demobox](https://github.com/demobox))

* Use separate client for leader election in scheduler to avoid starving leader election by regular scheduler operations. ([#53793](https://github.com/kubernetes/kubernetes/pull/53793), [@wojtek-t](https://github.com/wojtek-t))
* fix azure disk mounter issue ([#52260](https://github.com/kubernetes/kubernetes/pull/52260), [@andyzhangx](https://github.com/andyzhangx))

### Cloud Provider

* kube-apiserver: The external hostname no longer longer use the cloud provider API to select a default. It can be set explicitly using --external-hostname, if needed. If there is no default, AdvertiseAddress or os.Hostname() will be used, in that order. ([#56812](https://github.com/kubernetes/kubernetes/pull/56812), [@dims](https://github.com/dims))

- Client-go: Optimized leaders renewing leases by updating leader lock optimistically without getting the record from the API server first. Also, a new metric `leader_election_slowpath_total` was added to allow users to monitor how many leader elections are updated non-optimistically.

- LeaseLocks could now have custom labels that different holders would overwrite when they became the holder of the underlying lease. ([#131632](https://github.com/kubernetes/kubernetes/pull/131632), [@DerekFrank](https...

- Added a path `/header?key=` to `agnhost netexec` allowing one to view what the header value is of the incoming request.

  Ex:
  ```
  $ curl -H "X-Forwarded-For: something" 172.17.0.2:8080/header?key=X-Forwarded-For
  something
  ```

- Kubelet config file will be backed up to `/etc/kubernetes/tmp/` folder with `kubeadm-kubelet-config` append with a random suffix as the filename ([#114695](https://github.com/kubernetes/kubernetes/pull/114695), [@chendave](https://github.com/chendave)) [SIG Cluster Lifecycle]
- Kubelet no longer creates certain legacy iptables rules by default.

- Changed: default "Accept-Encoding" header removed from HTTP probes. See https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/#http-probes ([#96127](https://github.com/kubernetes/kubernetes/pull/96127), [@fonsecas72](https://github.com/fonsecas72)) [SIG Network and Node]