- Applications that fetch metrics from kube-scheduler should use a dedicated service account which is allowed to access nonResourceURLs `/metrics`. ([#96345](https://github.com/kubernetes/kubernetes/pull/96345), [@ingvagabund](https://github.com/ingvagabund)) [SIG Cloud Provider, Scheduling and Testing]

- Metric `running_managed_controllers` is enabled for Cloud Node Lifecycle controller. ([#111033](https://github.com/kubernetes/kubernetes/pull/111033), [@jprzychodzen](https://github.com/jprzychodzen))

    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
  - [Deprecations](#deprecations)
  - [Removed and deprecated metrics](#removed-and-deprecated-metrics)
    - [Removed metrics](#removed-metrics)
    - [Deprecated metrics](#deprecated-metrics)
  - [Notable Features](#notable-features)
  - [API Changes](#api-changes)
  - [Detailed Bug Fixes And Changes](#detailed-bug-fixes-and-changes)

      - [Storage](#storage)
    - [Deprecations and Removals](#deprecations-and-removals)
    - [Metrics Changes](#metrics-changes)
      - [Added metrics](#added-metrics)
      - [Removed metrics](#removed-metrics)
      - [Deprecated/changed metrics](#deprecated/changed-metrics)
    - [Notable Features](#notable-features)
      - [Beta](#beta)
      - [Alpha](#alpha)

- 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,...

- Metrics server nanny has now poll period set to 30s (previously 5 minutes) to allow faster scaling of metrics server. ([#101869](https://github.com/kubernetes/kubernetes/pull/101869), [@olagacek](https://github.com/olagacek)) [SIG Cloud Provider and Instrumentation]

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...

* 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))

* 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.

`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...