evicts pods from nodes in preparation for disruptive operations like kernel
upgrades or maintenance.
     * Custom Metrics for Autoscaling (HorizontalPodAutoscaler API in the Autoscaling
API group): The Horizontal Pod Autoscaling feature now supports custom metrics
(Alpha), allowing you to specify application-level metrics and thresholds to

* The `autoscaling/v2alpha1` API is now at `autoscaling/v2beta1`. However, the form of the API remains unchanged. Migrate the `HorizontalPodAutoscaler` resources to `autoscaling/v2beta1` to persist the `HorizontalPodAutoscaler` changes introduced in `autoscaling/v2alpha1`. The Horizontal Pod Autoscaler changes include support for status conditions, and autoscaling on memory and custom metrics.

### HorizontalPodAutoscaler v2 graduates to GA

Version 2 of the HorizontalPodAutoscaler API graduates to stable in the 1.23 release. The HorizontalPodAutoscaler `autoscaling/v2beta2` API is deprecated in favor of the new `autoscaling/v2` API, which the Kubernetes project recommends for all use cases.

This release does *not* deprecate the v1 HorizontalPodAutoscaler API.

* Introduces status conditions to the HorizontalPodAutoscaler in autoscaling/v2alpha1, indicating the current status of a given HorizontalPodAutoscaler, and why it is or is not scaling. ([#46550](https://github.com/kubernetes/kubernetes/pull/46550), [@DirectXMan12](https://github.com/DirectXMan12))

    * This fixed environments where CPU and Memory Accounting were not enabled on the unit that launched the kubelet or docker from reporting the root cgroup when monitoring usage stats for those components.
* New default horizontalpodautoscaler/v1 generator for kubectl autoscale. ([#26775](https://github.com/kubernetes/kubernetes/pull/26775), [@piosz](https://github.com/piosz))
    * Use autoscaling/v1 in kubectl by default.

### **Autoscaling**

*   HorizontalPodAutoscaler objects now properly functions on scalable resources in any API group. Fixed by adding a polymorphic scale client. ([#53743](https://github.com/kubernetes/kubernetes/pull/53743),[ @DirectXMan12](https://github.com/DirectXMan12))

- Added a new `tolerance` field to HorizontalPodAutoscaler, overriding the cluster-wide default. Enabled via the HPAConfigurableTolerance alpha feature gate. ([#130797](https://github.com/kubernetes/kubernetes/pull/130797), [@jm-franc](https://github.com/jm-franc)) [SIG API Machinery, Apps, Autoscaling,...

- Fix scheduler crash when removing node before its pods ([#89908](https://github.com/kubernetes/kubernetes/pull/89908), [@alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]
- Fixes conversion error for HorizontalPodAutoscaler objects with invalid annotations ([#89965](https://github.com/kubernetes/kubernetes/pull/89965), [@liggitt](https://github.com/liggitt)) [SIG Autoscaling]

* Introduces an new alpha version of the Horizontal Pod Autoscaler including expanded support for specifying metrics. ([#36033](https://github.com/kubernetes/kubernetes/pull/36033), [@DirectXMan12](https://github.com/DirectXMan12)
* HorizontalPodAutoscaler is no longer supported in extensions/v1beta1 version. Use autoscaling/v1 instead. ([#35782](https://github.com/kubernetes/kubernetes/pull/35782), [@piosz](https://github.com/piosz))

- Kubernetes is now built with Go 1.19.6 ([#115833](https://github.com/kubernetes/kubernetes/pull/115833), [@cpanato](https://github.com/cpanato)) [SIG Release and Testing]
- Use HorizontalPodAutoscaler v2 for kubectl ([#114886](https://github.com/kubernetes/kubernetes/pull/114886), [@a7i](https://github.com/a7i)) [SIG CLI]

### Bug or Regression