- Introduced a feature gate mechanism to `client-go`. Depending on the actual implementation, users can control features via environmental variables or command line options. ([#122555](https://github.com/kubernetes/kubernetes/pull/122555), [@p0lyn0mial](https://github.com/p0lyn0mial))

The Kubernetes Volume Snapshot feature is now beta in Kubernetes v1.17. It was introduced as alpha in Kubernetes v1.12, with a second alpha with breaking changes in Kubernetes v1.13.

### CSI Migration Beta

The Kubernetes in-tree storage plugin to Container Storage Interface (CSI) migration infrastructure is now beta in Kubernetes v1.17. CSI migration was introduced as alpha in Kubernetes v1.14.

## Known Issues

* Introduce API for watch bookmark events. ([#74074](https://github.com/kubernetes/kubernetes/pull/74074), [@wojtek-t](https://github.com/wojtek-t))

- 'Priority and Fairness has introduced a new feature called _borrowing_ that allows an API priority level
  to borrow a number of seats from other priority level(s). As a cluster operator, you can enable borrowing
  for a certain priority level configuration object via the two newly introduced fields `lendablePercent`, and

    - [Extending Ingress with and replacing a deprecated annotation with IngressClass](#extending-ingress-with-and-replacing-a-deprecated-annotation-with-ingressclass)
    - [SIG CLI introduces kubectl debug](#sig-cli-introduces-kubectl-debug)
    - [Introducing Windows CSI support alpha for Kubernetes](#introducing-windows-csi-support-alpha-for-kubernetes)
    - [Other notable announcements](#other-notable-announcements)

* Fix panic create/update CRD when mutating/validating webhook configured. ([#61404](https://github.com/kubernetes/kubernetes/pull/61404), [@hzxuzhonghu](https://github.com/hzxuzhonghu))
* Introduced `--http2-max-streams-per-connection` command line flag on api-servers and set default to 1000 for aggregated API servers. ([#60054](https://github.com/kubernetes/kubernetes/pull/60054), [@MikeSpreitzer](https://github.com/MikeSpreitzer))

  which is not allowed. ([#121667](https://github.com/kubernetes/kubernetes/pull/121667), [@kerthcet](https://github.com/kerthcet)) [SIG Scheduling]
- Fixes a kube-apiserver log volume regression bug in default 1.27 configurations (introduced in 1.26, activated by the AggregatedDiscoveryEndpoint feature enablement in 1.27) ([#122096](https://github.com/kubernetes/kubernetes/pull/122096), [@ritazh](https://github.com/ritazh)) [SIG API Machinery]

### SIG Storage

Sig Storage graduated two features that had been introduced in previous versions and introduced three new features in an alpha state.

- Introduced dynamic volume provisioning shim for CSI migration ([#73653](https://github.com/kubernetes/kubernetes/pull/73653), [@ddebroy](https://github.com/ddebroy))

- Introduce `OS` field in the PodSpec ([#104693](https://github.com/kubernetes/kubernetes/pull/104693), [@ravisantoshgudimetla](https://github.com/ravisantoshgudimetla))
- Introduce `v1beta3` API for scheduler. This version 
  - increases the weight of user specifiable priorities.