When adding links which point to resources within git repositories, like
KEPs or supporting documentation, please reference a specific commit and avoid
linking directly to the master branch. This ensures that links reference a
specific point in time, rather than a document that may change over time.

 - The `batch/v2alpha1.CronJob` is deprecated in favor of `batch/v1beta1`.

 - The `batch/v2alpha1.ScheduledJob` was removed. Use `batch/v1beta1.CronJob` instead.

### Auth

 - The RBAC v1alpha1 API group is deprecated in favor of RBAC v1.

* Support metrics API in `kubectl top` commands. ([#56206](https://github.com/kubernetes/kubernetes/pull/56206), [@brancz](https://github.com/brancz))

* Bump GCE metadata proxy to v0.1.9 to pick up security fixes. ([#58221](https://github.com/kubernetes/kubernetes/pull/58221), [@ihmccreery](https://github.com/ihmccreery))

- Pods owned by a Job now uses the labels `batch.kubernetes.io/job-name` and `batch.kubernetes.io/controller-uid`.

### **Instrumentation**

#### **Audit**

*   Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417),[ @crassirostris](https://github.com/crassirostris))

- The PodSecurityPolicy API is deprecated in 1.21, and will no longer be served starting in 1.25. ([#97171](https://github.com/kubernetes/kubernetes/pull/97171), [@deads2k](https://github.com/deads2k)) [SIG Auth and CLI]
- The `batch/v2alpha1` CronJob type definitions and clients are deprecated and removed. ([#96987](https://github.com/kubernetes/kubernetes/pull/96987), [@soltysh](https://github.com/soltysh)) [SIG API Machinery, Apps, CLI and Testing]

* Upgrade golang.org/x/net image to release-branch.go1.10 ([#70663](https://github.com/kubernetes/kubernetes/pull/70663), [@wenjiaswe](https://github.com/wenjiaswe))

* apiserver: fixes handling and logging of panics in REST handlers to prevent crashes ([#71076](https://github.com/kubernetes/kubernetes/pull/71076), [@liggitt](https://github.com/liggitt))
* Upgrade golang.org/x/net image to release-branch.go1.10 ([#70663](https://github.com/kubernetes/kubernetes/pull/70663), [@wenjiaswe](https://github.com/wenjiaswe))

- Added `kubelet_container_log_size_bytes` metric representing the log file size of a container. ([#70749](https://github.com/kubernetes/kubernetes/pull/70749), [@brancz](https://github.com/brancz))

- Added `--concurrency` flag to configure the concurrency of `kubectl diff` execution, defaults to 1. ([#118810](https://github.com/kubernetes/kubernetes/pull/118810), [@brancz](https://github.com/brancz))
- Added `ConsistentListFromCache` feature gate that allows apiserver to serve consistent lists from cache. ([#118508](https://github.com/kubernetes/kubernetes/pull/118508), [@serathius](https://github.com/serathius))