Implementation restriction:
A union (with more than one term) cannot contain the
<a href="#Predeclared_identifiers">predeclared identifier</a> <code>comparable</code>
or interfaces that specify methods, or embed <code>comparable</code> or interfaces
that specify methods.
</p>

<p>
Interfaces that are not <a href="#Basic_interfaces">basic</a> may only be used as type
constraints, or as elements of other interfaces used as constraints.

- **[beta]** [Taints and tolerations](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/). This feature allows you to specify rules for "repelling" pods from nodes by default, which enables use cases like dedicated nodes and reserving nodes with special features for pods that need those features. We've also added a `NoExecute` taint type that evicts already-running pods, and an associated `tolerationSeconds` field to tolerations to delay...

- Users can now specify azure file share name in the azure file plugin, making it possible to use existing shares or specify a new share name. ([#76988](https://github.com/kubernetes/kubernetes/pull/76988), [@andyzhangx](https://github.com/andyzhangx))

## Major Themes

Kubernetes is developed by community members whose work is organized into
[Special Interest Groups][]. For the 1.8 release, each SIG provides the
themes that guided their work.

[Special Interest Groups]: https://github.com/kubernetes/community/blob/master/sig-list.md

### SIG API Machinery

  // even if they are not included in this list.
  // Note that this field cannot be set when spec.os.name is windows.
  // +optional
  repeated int64 supplementalGroups = 4;

  // A special supplemental group that applies to all containers in a pod.
  // Some volume types allow the Kubelet to change the ownership of that volume
  // to be owned by the pod:
  //
  // 1. The owning GID will be the FSGroup

* Fix mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufied](https://github.com/gnufied))

provider can now be specified as environment variables. When we convert the OpenStack cloud provider to run in an external process, we can now use the kubernetes Secrets capability to inject the OS_* variables. This way we can specify the cloud configuration as a configmap, and specify secrets for the userid/password information. The configmap is mounted as a file, and the secrets are made available as environment variables. The external controller itself runs as a pod/daemonset. For backward compatibility,...

### Other notable changes

* Added new flag to `kubeadm init`: --node-name, that lets you specify the name of the Node object that will be created ([#48594](https://github.com/kubernetes/kubernetes/pull/48594), [@GheRivero](https://github.com/GheRivero))

* Add mechanism for Admission Webhooks to specify which version of AdmissionReview they support ([#74998](https://github.com/kubernetes/kubernetes/pull/74998), [@mbohlool](https://github.com/mbohlool))
    * Add mechanism for CRD Conversion Webhooks to specify which version of ConversionReview they support

  behind the `DynamicResourceAllocation` feature gate).
  The new API is now more flexible than the existing Device Plugins feature of Kubernetes because it
  allows Pods to request (claim) special kinds of resources, which can be available at node level, cluster
  level, or following any other model you implement.' ([#111023](https://github.com/kubernetes/kubernetes/pull/111023), [@pohly](https://github.com/pohly))