*   Apply algorithm in scheduler by feature gates. ([#52723](https://github.com/kubernetes/kubernetes/pull/52723),[ @k82cn](https://github.com/k82cn))

    * Use PreFilter instead of Prefilter in the scheduling framework
    * Use PreBind instead of Prebind in the scheduling framework
* Fix `kubectl logs -f` for windows server containers. ([#81747](https://github.com/kubernetes/kubernetes/pull/81747), [@Random-Liu](https://github.com/Random-Liu))

- Added a alpha feature, behind the `RelaxedEnvironmentVariableValidation` feature gate.
  When that gate is enabled, Kubernetes allows almost all printable ASCII characters to be used in the names

  `v1beta2/v1beta3/v1`.'
   ([#113275](https://github.com/kubernetes/kubernetes/pull/113275), [@Huang-Wei](https://github.com/Huang-Wei))
- 'Added a `ResourceClaim` API (in the `resource.k8s.io/v1alpha1` API group and
  behind the `DynamicResourceAllocation` feature gate).
  The new API is now more flexible than the existing Device Plugins feature of Kubernetes because it

### Avoiding permanent beta

From Kubernetes 1.20 onwards, SIG Architecture will implement a new policy to transition all REST APIs out of beta within nine months. The idea behind the new policy is to avoid features staying in beta for a long time. Once a new API enters beta, it will have nine months to either:

 - reach GA, and deprecate the beta, or

* Introduce Alpha field `Immutable` in both Secret and ConfigMap objects to mark their contents as immutable. The implementation is hidden behind feature gate `ImmutableEphemeralVolumes` (currently in Alpha stage). ([#86377](https://github.com/kubernetes/kubernetes/pull/86377), [@wojtek-t](https://github.com/wojtek-t))

* Fix kubelet reset liveness probe failure count across pod restart boundaries ([#46371](https://github.com/kubernetes/kubernetes/pull/46371), [@sjenning](https://github.com/sjenning))
* The gce metadata server can be hidden behind a proxy, hiding the kubelet's token. ([#45565](https://github.com/kubernetes/kubernetes/pull/45565), [@Q-Lee](https://github.com/Q-Lee))

  feature gates enabled) that their pods could get stuck in the pending phase when deleted.
  
  Users who maintain controllers which relied on the fact that pods with RestartPolicy=Always
  never enter the Succeeded phase may need to adapt their controllers. This is because as a consequence of 

### Pod Hostname as FQDN graduates to Beta

$figure-caption-color;\n}\n","// Image Mixins\n// - Responsive image\n// - Retina image\n\n\n// Responsive image\n//\n// Keep images from scaling beyond the width of their parents.\n\n@mixin img-fluid() {\n  // Part 1: Set a maximum relative to the parent\n  max-width: 100%;\n  // Part 2: Override the height to auto, otherwise images will be stretched\n  // when setting a width and height attribute on the img element.\n  height: auto;\n}\n\n\n// Retina image\n//\n// Short retina mixin for setting background-image...