For more information, see [#53288](https://issue.k8s.io/53288).

* `kubeadm init` and `kubeadm join` invocations on newly installed systems can encounter a `/var/lib/kubelet is not empty` message during pre-flight checks that prevents setup. If this is the only pre-flight failure, it can be safely ignored with `--skip-preflight-checks`.

For more information, see [#53356](https://issue.k8s.io/53356#issuecomment-333748618).

- Added a `Processing` condition for the `workqueue` API.
  Changed `Shutdown` for the `workqueue` API to wait until the work queue finishes processing all in-flight items. ([#101928](https://github.com/kubernetes/kubernetes/pull/101928), [@alexanderConstantinescu](https://github.com/alexanderConstantinescu))

   The `read_vs_write_current_requests` metric histogram is adjusted, in the case of using API Priority and Fairness instead of max-in-flight, to divide by the relevant limit: sum of queue capacities for waiting requests, sum of seat limits for executing requests. ([#110164](https://github.com/kubernetes/kubernetes/pull/110164), [@MikeSpreitzer](https://github.com/MikeSpreitzer))

* Add apiserver metric for number of requests dropped because of inflight limit. ([#58340](https://github.com/kubernetes/kubernetes/pull/58340), [@gmarek](https://github.com/gmarek))
* Add apiserver metric for current inflight-request usage. ([#58342](https://github.com/kubernetes/kubernetes/pull/58342), [@gmarek](https://github.com/gmarek))

* scheduler: use incremental scheduling cycle in PriorityQueue to put all in-flight unschedulable pods back to active queue if we received move request ([#73309](https://github.com/kubernetes/kubernetes/pull/73309), [@cofyc](https://github.com/cofyc))

    * b. kubectl get pod test-pod -o custom-columns=CONTAINER:.spec.containers[-2:].name
* scheduler: use incremental scheduling cycle in PriorityQueue to put all in-flight unschedulable pods back to active queue if we received move request ([#73309](https://github.com/kubernetes/kubernetes/pull/73309), [@cofyc](https://github.com/cofyc))

    Potential impacts:

  After the connection closed(received GOAWAY), the client's other in-flight requests won't be affected, and the client will reconnect. 
  The flag min value is 0 (off), max is .02 (1/50 requests); .001 (1/1000) is a recommended starting point.

* scheduler: use incremental scheduling cycle in PriorityQueue to put all in-flight unschedulable pods back to active queue if we received move request ([#73309](https://github.com/kubernetes/kubernetes/pull/73309), [@cofyc](https://github.com/cofyc))

- Overall, enable the feature of `PreferNominatedNode` will  improve the performance of scheduling where preemption might frequently happen, but in theory, enable the feature of `PreferNominatedNode`, the pod might not be scheduled to the best candidate node in the cluster. ([#93179](https://github.com/kubernetes/kubernetes/pull/93179), [@chendave](https://github.com/chendave)) [SIG Scheduling and Testing]