all API calls had to fetch key/value stored in secret and use it to authenticate/authorize these operations. With this change API calls receive key/value as a input parameter so they not need to know where and how credentials were stored and fetched. Main goal was to make these API calls CO (Container Orchestrator) agnostic.  ([#60118](https://github.com/kubernetes/kubernetes/pull/60118), [@sbezverk](https://github.com/sbezverk))

* StorageOS volume plugin has been updated to support mount...

- Migrated the main kube-controller-manager binary to use [contextual logging](https://k8s.io/docs/concepts/cluster-administration/system-logs/#contextual-logging). ([#116529](https://github.com/kubernetes/kubernetes/pull/116529), [@pohly](https://github.com/pohly))

### SIG Cloud Provider

* Restored cAdvisor prometheus metrics to the main port -- a regression that existed in v1.7.0-v1.7.2 ([#49079](https://github.com/kubernetes/kubernetes/pull/49079), [@smarterclayton](https://github.com/smarterclayton))

### Etcd v3.5.[0-2] data corruption

Data corruption issue was found in etcd v3.5.0 release that was shipped with 1.22 Kubernetes release. Please read up-to-date [production recommendations for etcd](https://github.com/etcd-io/etcd/tree/main/CHANGELOG).

## Changes by Kind

### Deprecation

`v1beta1.KubeletConfiguration`. The new patch target is called `kubeletconfiguration` (e.g. patch file `kubeletconfiguration+json.json`).This makes it possible to apply node specific KubeletConfiguration options during `init`, `join` and `upgrade`, while the main `KubeletConfiguration` that is passed to `init` as part of the `--config` file can still act as the global stored in the cluster `KubeletConfiguration`. ([#110405](https://github.com/kubernetes/kubernetes/pull/110405), [@neolit123](https://github.com/neolit123))...

  - apiserver_flowcontrol_current_r: R(the time of the last change in state of the queues)
  - apiserver_flowcontrol_dispatch_r: R(the time of the latest request dispatch)
  - apiserver_flowcontrol_latest_s: S(the request last dispatched) = R(when that request starts executing in the virtual world)
  - apiserver_flowcontrol_next_s_bounds: min and max next S among non-empty queues

Kubernetes 1.15 consists of **25 enhancements**: 2 moving to stable, 13 in beta, and 10 in alpha. The main themes of this release are:

#### Continuous Improvement

- Added a new scheduler metric, `pod_scheduling_sli_duration_seconds`,...

    * faster handoff when a leader-elected process is gracefully terminated.
* Make volume binder resilient to races between main schedule loop and async binding operation  ([#72045](https://github.com/kubernetes/kubernetes/pull/72045), [@cofyc](https://github.com/cofyc))