`autoscaling/v2alpha1`. The Horizontal Pod Autoscaler changes include support for status conditions, and autoscaling on memory and custom metrics.

* The metrics APIs, `custom-metrics.metrics.k8s.io` and `metrics`, were moved from `v1alpha1` to `v1beta1`, and renamed to `custom.metrics.k8s.io` and `metrics.k8s.io`, respectively. If you have deployed a custom metrics adapter, ensure that it supports the new API version. If you have deployed Heapster in aggregated API server mode, upgrade Heapster...

      - [Scheduling](#scheduling)
      - [Storage](#storage)
      - [Windows](#windows)
  - [Deprecations and Removals](#deprecations-and-removals)
  - [Metrics Changes](#metrics-changes)
    - [Added metrics](#added-metrics)
    - [Deprecated/changed metrics](#deprecatedchanged-metrics)
  - [Notable Features](#notable-features)
    - [Stable](#stable)
    - [Beta](#beta)
    - [CLI Improvements](#cli-improvements)

- resource metrics endpoint `/metrics/resource/v1alpha1` as well as all metrics under this endpoint have been deprecated. Please convert to the following metrics emitted by endpoint `/metrics/resource`:
  - scrape_error --> scrape_error
  - node_cpu_usage_seconds_total --> node_cpu_usage_seconds

* Migrate the metrics/v1alpha1 API to metrics/v1beta1.  The HorizontalPodAutoscaler ([#51653](https://github.com/kubernetes/kubernetes/pull/51653), [@DirectXMan12](https://github.com/DirectXMan12))
    * controller REST client now uses that version.  For v1beta1, the API is now known as
    * resource-metrics.metrics.k8s.io.

- Cloud controller manager's node controller now emits timing metrics for initial `Node` synchronization. These metrics measure the delay between the creation of a new `Node` and the node controller's initial management actions, such as removing the cloud provider taint. These metrics should be consulted when setting cloud controller manager's `--concurrent-node-syncs` flag. ([#119241](https://github.com/kubernetes/kubernetes/pull/119241),...

* The Metrics Server now exposes metrics via the /metric endpoint. These metrics are in the prometheus format.  ([#57456](https://github.com/kubernetes/kubernetes/pull/57456), [@kawych](https://github.com/kawych))

- Metrics can now be disabled explicitly via a command line flag (i.e. '--disabled-metrics=metric1,metric2') ([#99217](https://github.com/kubernetes/kubernetes/pull/99217), [@logicalhan](https://github.com/logicalhan))

- HPA controller exposes the following metrics from the kube-controller-manager. 
  - `metric_computation_duration_seconds`: The time(seconds) that the HPA controller takes to calculate one metric.

- Autoscaling/v2beta2 and custom_metrics/v1beta2 have been introduced, which implement metric selectors for Object and Pods metrics, as well as allowing AverageValue targets on Objects, similar to External metrics. ([#64097](https://github.com/kubernetes/kubernetes/pull/64097), [@damemi](https://github.com/damemi)) Courtesy of SIG API Machinery, SIG Architecture, SIG Autoscaling,...

has been deprecated as part of the deprecation of Heapster. Instead, you may use the [metrics server](https://github.com/kubernetes-incubator/metrics-server). It's a simplified heapster that is able to gather and serve current metrics values. It provides the Metrics API that is used by `kubectl top`, and horizontal pod autoscaler. Note that it doesn't include some features of Heapster, such as short term metrics for graphs in kube-dashboard and dedicated push sinks, which proved hard to maintain and...