### **Instrumentation**

#### **Audit**

*   Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417),[ @crassirostris](https://github.com/crassirostris))

- Fixed a panic in `kubectl exec` when the terminal size queue delegate is uninitialized. ([#136280](https://github.com/kubernetes/kubernetes/pull/136280), [@seekskyworld](https://github.com/seekskyworld)) [SIG CLI]

- Added `SchedulerPopFromBackoffQ` feature gate that is in beta and enabled by default. Improved scheduling queue behavior by popping pods from the backoffQ when the activeQ is empty. This allows to process potentially schedulable pods ASAP, eliminating a penalty effect of the backoff queue. ([#130772](https://github.com/kubernetes/kubernetes/pull/130772), [@macsko](https://github.com/macsko)) [SIG Scheduling and Testing]

    - `scheduler_async_api_call_duration_seconds`: histogram of API call execution duration by call type and result
    - `scheduler_pending_async_api_calls`: gauge showing current number of pending API calls in the queue. ([#133120](https://github.com/kubernetes/kubernetes/pull/133120), [@utam0k](https://github.com/utam0k)) [SIG Release and Scheduling]

### Scheduling

- Improved fairness of the scheduling queue by placing pods which are attempted recently behind other pods with the same priority. ([#73700](https://github.com/kubernetes/kubernetes/pull/73700), [@denkensk](https://github.com/denkensk))

* Change default value of deleting-pods-burst to 1 ([#27606](https://github.com/kubernetes/kubernetes/pull/27606), [@gmarek](https://github.com/gmarek))
* MESOS: fix race condition in contrib/mesos/pkg/queue/delay ([#24916](https://github.com/kubernetes/kubernetes/pull/24916), [@jdef](https://github.com/jdef))

/**
 * Static utility methods pertaining to {@link Map} instances (including instances of {@link
 * SortedMap}, {@link BiMap}, etc.). Also see this class's counterparts {@link Lists}, {@link Sets}
 * and {@link Queues}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#maps">{@code Maps}</a>.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock

/**
 * Static utility methods pertaining to {@link Map} instances (including instances of {@link
 * SortedMap}, {@link BiMap}, etc.). Also see this class's counterparts {@link Lists}, {@link Sets}
 * and {@link Queues}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#maps">{@code Maps}</a>.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock

* Making DHCP_OPTION_SET_ID creation optional ([#27278](https://github.com/kubernetes/kubernetes/pull/27278), [@activars](https://github.com/activars))
* Convert service account token controller to use a work queue ([#23858](https://github.com/kubernetes/kubernetes/pull/23858), [@liggitt](https://github.com/liggitt))

- Refactor scheduler's framework permit API. ([#83756](https://github.com/kubernetes/kubernetes/pull/83756), [@hex108](https://github.com/hex108))
- Add incoming pods metrics to scheduler queue. ([#83577](https://github.com/kubernetes/kubernetes/pull/83577), [@liu-cong](https://github.com/liu-cong))