- `client-go`, using log level 9, traces the following events of a HTTP request:
      - DNS lookup
      - TCP dialing
      - TLS handshake
      - Time to get a connection from the pool
      - Time to process a request ([#105156](https://github.com/kubernetes/kubernetes/pull/105156), [@aojea](https://github.com/aojea))

### Documentation

* Update Azure load balancer to prevent orphaned public IP addresses ([#82890](https://github.com/kubernetes/kubernetes/pull/82890), [@chewong](https://github.com/chewong))
* Fixes a goroutine leak in kube-apiserver when a request times out. ([#83333](https://github.com/kubernetes/kubernetes/pull/83333), [@lavalamp](https://github.com/lavalamp))

- Implemented `event_handling_duration_seconds` metric, which is the time the scheduler takes to handle each kind of events. ([#125929](https://github.com/kubernetes/kubernetes/pull/125929), [@sanposhiho](https://github.com/sanposhiho))

- Because of the implementation logic of `time.Format` in golang, the displayed time zone is not consistent. ([#102366](https://github.com/kubernetes/kubernetes/pull/102366), [@cndoit18](https://github.com/cndoit18))

* Fix watch to not send the same set of events multiple times causing watcher to go back in time ([#73845](https://github.com/kubernetes/kubernetes/pull/73845), [@wojtek-t](https://github.com/wojtek-t))

  - Clone `kubernetes/kubernetes` in `update-vendor.sh` shallowly, instead of fetching all revisions
  - Speed up binpacking by reducing the number of PreFilter calls (call once per pod instead of #pods*#nodes times)
  - Speed up finding unneeded nodes by 5x+ in very large clusters by reducing the number of PreFilter calls
  - Expose `--max-nodes-total` as a metric

## Changes by Kind

### Feature

- Kubeadm: generate CA certificates with a start time that is offset 5 minutes in the past relative to the current system time to workaround cases of clock desync.

  For more information, see [#56348](https://github.com/kubernetes/kubernetes/issues/56348).

*   API server times out after performing a rolling update of the etcd cluster. This issue will be fixed in a future release.

  For more information, see [#47131](https://github.com/kubernetes/kubernetes/issues/47131)

* Update Cluster Autoscaler to version 1.3.7. ([#74136](https://github.com/kubernetes/kubernetes/pull/74136), [@jkaniuk](https://github.com/jkaniuk))
* Fix watch to not send the same set of events multiple times causing watcher to go back in time ([#73845](https://github.com/kubernetes/kubernetes/pull/73845), [@wojtek-t](https://github.com/wojtek-t))

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