- The RuntimeClass API has been added. This feature is in alpha, and the RuntimeClass feature gate must be enabled in order to use it. The RuntimeClass API resource defines different classes of runtimes that may be used to run containers in the cluster. Pods can select a RuntimeClass to use via the RuntimeClassName field. ([#67737](https://github.com/kubernetes/kubernetes/pull/67737), [@tallc...

### Alpha

  // This field will be autopopulated at admission time by the RuntimeClass admission controller. If
  // the RuntimeClass admission controller is enabled, overhead must not be set in Pod create requests.
  // The RuntimeClass admission controller will reject Pod create requests which have the overhead already

	// This field will be autopopulated at admission time by the RuntimeClass admission controller. If
	// the RuntimeClass admission controller is enabled, overhead must not be set in Pod create requests.
	// The RuntimeClass admission controller will reject Pod create requests which have the overhead already

"Overhead represents the resource overhead associated with running a pod for a given RuntimeClass. This field will be autopopulated at admission time by the RuntimeClass admission controller. If the RuntimeClass admission controller is enabled, overhead must not be set in Pod create requests. The RuntimeClass admission controller will reject Pod create requests which have the overhead already set. If RuntimeClass is configured and selected in the PodSpec, Overhead will be set to the value defined...

  // This field will be autopopulated at admission time by the RuntimeClass admission controller. If
  // the RuntimeClass admission controller is enabled, overhead must not be set in Pod create requests.
  // The RuntimeClass admission controller will reject Pod create requests which have the overhead already

### Action Required

	// This field will be autopopulated at admission time by the RuntimeClass admission controller. If
	// the RuntimeClass admission controller is enabled, overhead must not be set in Pod create requests.
	// The RuntimeClass admission controller will reject Pod create requests which have the overhead already

"Overhead represents the resource overhead associated with running a pod for a given RuntimeClass. This field will be autopopulated at admission time by the RuntimeClass admission controller. If the RuntimeClass admission controller is enabled, overhead must not be set in Pod create requests. The RuntimeClass admission controller will reject Pod create requests which have the overhead already set. If RuntimeClass is configured and selected in the PodSpec, Overhead will be set to the value defined...

- Added RuntimeClass restrictions and defaulting to PodSecurityPolicy. ([#73795](https://github.com/kubernetes/kubernetes/pull/73795), [@tallclair](https://github.com/tallclair))