- The `CustomResourceDefaulting` feature is promoted to beta and enabled by default. Defaults may be specified in structural schemas via the `apiextensions.k8s.io/v1` API. See https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/#specifying-a-structural-schema for details. ([#81872](https://github.com/kubernetes/kubernetes/pull/81872), [@sttts](https://github.com/sttts))

* kube-apiserver: The `AdmissionConfiguration` type accepted by `--admission-control-config-file` has been promoted to `apiserver.config.k8s.io/v1` with no schema changes. ([#85098](https://github.com/kubernetes/kubernetes/pull/85098), [@liggitt](https://github.com/liggitt))...

- Fix performance issue when creating large objects using SSA with fully unspecified schemas (preserveUnknownFields). ([#111914](https://github.com/kubernetes/kubernetes/pull/111914), [@aojea](https://github.com/aojea)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Storage and Testing]

- Introduced OpenAPI format support for `k8s-short-name` and `k8s-long-name` in CustomResourceDefinition schemas. ([#132504](https://github.com/kubernetes/kubernetes/pull/132504), [@jpbetz](https://github.com/jpbetz)) [SIG API Machinery, Architecture, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Scheduling and Storage]

- Fixed performance issue when creating large objects using SSA with fully unspecified schemas ( preserveUnknownFields ). ([#111557](https://github.com/kubernetes/kubernetes/pull/111557), [@alexzielenski](https://github.com/alexzielenski))

* Add port forwarding for rkt with kvm stage1 ([#32126](https://github.com/kubernetes/kubernetes/pull/32126), [@jjlakis](https://github.com/jjlakis))

  - The `/swaggerapi/*` schema docs, deprecated since 1.7, have been removed in favor of the /openapi/v2 schema docs. ([#72924](https://github.com/kubernetes/kubernetes/pull/72924), [@liggitt](https://github.com/liggitt))

- Fixed nil pointer error in `NodeVolumeLimits` csi logging ([#115179](https://github.com/kubernetes/kubernetes/pull/115179), [@sunnylovestiramisu](https://github.com/sunnylovestiramisu))
- Fixed panic validating custom resource definition schemas that set `multipleOf` to 0 ([#114869](https://github.com/kubernetes/kubernetes/pull/114869), [@liggitt](https://github.com/liggitt))

    proxies.add(proxy)
    return this
  }

  override fun select(uri: URI): List<Proxy> {
    // Don't handle 'socket' schemes, which the RI's Socket class may request (for SOCKS).
    return if (uri.scheme == "http" || uri.scheme == "https") proxies else listOf(Proxy.NO_PROXY)
  }

  override fun connectFailed(
    uri: URI,
    sa: SocketAddress,
    ioe: IOException,
  ) {
  }

## Changelog since v1.20.11

## Changes by Kind

### API Change

- Kube-apiserver: Fixes handling of CRD schemas containing literal null values in enums (#104990, @liggitt) [SIG API Machinery, Apps and Network]

### Bug or Regression