- Apiserver add a new flag --goaway-chance which is the fraction of requests that will be closed gracefully(GOAWAY) to prevent HTTP/2 clients from getting stuck on a single apiserver. 
  After the connection closed(received GOAWAY), the client's other in-flight requests won't be affected, and the client will reconnect. 

- Fixes regression in logging spurious stack traces when proxied connections are closed by the backend ([#82588](https://github.com/kubernetes/kubernetes/pull/82588), [@liggitt](https://github.com/liggitt))

- Fix kubelet to not leak goroutines/intofiy watchers on an inactive connection if it's closed ([#67285](https://github.com/kubernetes/kubernetes/pull/67285), [@yujuhong](https://github.com/yujuhong))

* rbd: default image format to v2 instead of deprecated v1 ([#51574](https://github.com/kubernetes/kubernetes/pull/51574), [@dillaman](https://github.com/dillaman))
* Surface reasonable error when client detects connection closed. ([#51381](https://github.com/kubernetes/kubernetes/pull/51381), [@mengqiy](https://github.com/mengqiy))

/kind api-change
/kind deprecation
/kind failing-test
/kind flake
/kind regression
-->

#### What this PR does / why we need it:

#### Which issue(s) this PR fixes:
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Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
_If PR is about `failing-tests or flakes`, please post the related issues/tests in a comment and do not use `Fixes`_*
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Fixes #

* admission webhook registrations without a specific failure policy default to failing closed. ([#54162](https://github.com/kubernetes/kubernetes/pull/54162), [@deads2k](https://github.com/deads2k))

## Changelog since v1.10.11

### Other notable changes

* Updates defaultbackend to 1.5 ([#69381](https://github.com/kubernetes/kubernetes/pull/69381), [@bowei](https://github.com/bowei))
* Immediately close the other side of the connection when proxying. ([#67288](https://github.com/kubernetes/kubernetes/pull/67288), [@MHBauer](https://github.com/MHBauer))

- The Kubernetes API server now correctly detects and closes existing TLS connections when its client certificate file for kubelet authentication has been rotated. ([#115315](https://github.com/kubernetes/kubernetes/pull/115315), [@enj](https://github.com/enj)) [SIG API Machinery, Auth, Node and Testing]

- `DelayingQueue.ShutDown()` can now be invoked multiple times without causing a closed channel panic. ([#77170](https://github.com/kubernetes/kubernetes/pull/77170), [@smarterclayton](https://github.com/smarterclayton))

- Fixed admission metrics in seconds. ([#72343](https://github.com/kubernetes/kubernetes/pull/72343), [@danielqsj](https://github.com/danielqsj))
- When a watch is closed by an HTTP2 load balancer and we are told to go away, skip printing the message to stderr by default.