Add a KEP for graduating pod priority and preemption to GA

keps/sig-scheduling/201901031-pod-priority-preemption.md

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+---
+title: Promote Pod Priority and Preemption to GA
+authors:
+  - "@bsalamat"
+owning-sig: sig-scheduling
+participating-sigs:
+  - sig-scheduling
+reviewers:
+  - "@k82cn"
+approvers:
+  - "@liggitt"
+editor: Babak Salamat
+creation-date: 2019-01-31
+last-updated: 2017-01-31
+status: impementable
+see-also:
+replaces:
+superseded-by:
+---
+
+# Promote Pod Priority and Preemption to GA
+
+## Table of Contents
+
+* [Table of Contents](#table-of-contents)
+* [Summary](#summary)
+* [Motivation](#motivation)
+    * [Goals](#goals)
+    * [Non-Goals](#non-goals)
+* [Proposal](#proposal)
+    * [Risks and Mitigations](#risks-and-mitigations)
+* [Graduation Criteria](#graduation-criteria)
+* [Implementation History](#implementation-history)
+
+
+## Summary
+
+Pod Priority and Preemption are features introduced in Kubernetes 1.8 as alpha features and 
+promoted to beta in 1.11. Pod Priority enables users to specify importance of
+a Pod. Pods with higher priority are scheduled ahead of other pods with
+lower priority. When a cluster does not enough capacity for running a high
+priority pod, the scheduler preempts and removes lower priority pods in order to
+make room for the high priority pod.
+
+## Motivation
+
+Pod Priority and Preemption have existed in the past several releases and some
+of our most critical components of Kubernetes, i.e. critical DaemonSet Pods,
+rely on this feature for guaranteed scheduling since Kubernetes 1.12.
+
+### Goals
+
+Promote Pod Priority and Preemption to GA.
+
+### Non-Goals
+
+Make any change of functionality to the features.
+
+## Proposal
+
+Create `scheduling.k8s.io/v1` API group and add `PriorityClass` to it.
+
+Make necessary changes to our code base to use `scheduling.k8s.io/v1` instead of
+`scheduling.k8s.io/v1beta1`.
+
+Update our documentation to reflect the new version and status of the features.
+
+### Risks and Mitigations
+
+Given that there is no functionality changes, we don't expect any logical errors
+caused by this change.
+
+## Graduation Criteria
+
+* The features have been stable and reliable in the past several releases.
+* Adequate documentation exists for the features.
+* Test coverage of the features is acceptable.
+
+## Implementation History
+
+Pod Priority and Preemption are tracked as part of [enhancement#564](https://github.com/kubernetes/enhancements/issues/564).
+The proposal for Pod Priority can be [found here](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/scheduling/pod-priority-api.md)
+and Preemption proposal is [here](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/scheduling/pod-preemption.md).