- '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

    * Default value for expendable pod priority cutoff in GCP deployment of Cluster Autoscaler changed from 0 to -10.
    * action required: users deploying workloads with priority lower than 0 may want to use priority lower than -10 to avoid triggering scale-up.

### Other notable changes

*   Apply algorithm in scheduler by feature gates. ([#52723](https://github.com/kubernetes/kubernetes/pull/52723),[ @k82cn](https://github.com/k82cn))

- Expand scheduler priority functions and scheduling framework plugins' node score range to [0, 100]. Note: this change is internal and does not affect extender and RequestedToCapacityRatio custom priority, which are still expected to provide a [0, 10] range. ([#83522](https://github.com/kubernetes/kubernetes/pull/83522), [@draveness](https://github.com/draveness))...

  
  action required

### API Priority and Fairness graduates to Beta

Initially introduced in 1.18, Kubernetes 1.20 now enables API Priority and Fairness (APF) by default. This allows `kube-apiserver` to [categorize incoming requests by priority levels](https://docs.k8s.io/concepts/cluster-administration/flow-control/).

### IPv4/IPv6 run

    * Default value for expendable pod priority cutoff in GCP deployment of Cluster Autoscaler changed from 0 to -10.
    * action required: users deploying workloads with priority lower than 0 may want to use priority lower than -10 to avoid triggering scale-up.

#### Scheduling

* [alpha] This version now supports pod priority and creation of PriorityClasses ([user doc](https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/))([design doc](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/scheduling/pod-priority-api.md))

Pod Priority and Preemption in Kubernetes ([#564](https://github.com/kubernetes/enhancements/issues/564))

- Pod priority and preemption enables Kubernetes scheduler to schedule more important Pods first and when cluster is out of resources, it removes less important pods to create room for more important ones. The importance is specified by priority.

## Changelog since v1.18.18

## Changes by Kind

### API Change

- We have added a new Priority & Fairness rule that exempts all probes (/readyz, /healthz, /livez) to prevent