- Registered_metric_total, disabled_metric_total, hidden_metric_total & kubernetes_feature_enabled are promoted to `BETA` stability. ([#119264](https://github.com/kubernetes/kubernetes/pull/119264), [@logicalhan](https://github.com/logicalhan)) [SIG API Machinery, Architecture, Cluster Lifecycle...

      - [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

- 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...

- Component owner can configure the allowlist of metric label with flag '--allow-metric-labels'. ([#99385](https://github.com/kubernetes/kubernetes/pull/99385), [@YoyinZyc](https://github.com/YoyinZyc)) [SIG API Machinery, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation and Release]

`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...

- 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.

* Flex drivers by default do not produce metrics. Flex plugins can enable metrics collection by setting  the capability 'supportsMetrics' to true. Make sure the file system can support fs stat to produce metrics in this case. ([#67508](https://github.com/kubernetes/kubernetes/pull/67508), [@brahmaroutu](https://github.com/brahmaroutu))

### Pod resource metrics

On-demand metrics calculation is now available through `/metrics/resources`. [When enabled](
https://docs.k8s.io/concepts/cluster-administration/system-metrics#kube-scheduler-metrics), the endpoint will report the requested resources and the desired limits of all running pods.

### Introducing `RootCAConfigMap`