## API Changes

- [CRI] Added a new field called `runtime_handler` into `PodSandbox` and `PodSandboxStatus` to track the `RuntimeClass` information of a pod. ([#73833](https://github.com/kubernetes/kubernetes/pull/73833), [@haiyanmeng](https://github.com/haiyanmeng))

- CRI now supports a "runtime_handler" field for RunPodSandboxRequest, used for selecting the runtime configuration to run the sandbox with (alpha feature). ([#67518](https://github.com/kubernetes/kubernetes/pull/67518), [@tallclair](https://github.com/tallclair))

  // runtime (using native Linux containers) will be used to run the containers
  // in a pod.
  // The runtimeHandler must be lowercase, conform to the DNS Label (RFC 1123)
  // requirements, and is immutable.
  optional string runtimeHandler = 1;

  // overhead represents the resource overhead associated with running a pod for a
  // given RuntimeClass. For more details, see

- Added new feature gate called `RuntimeClassInImageCriApi` to address `kubelet` changes needed for KEP 4216.
  Noteable changes:
  1. Populate new `RuntimeHandler` field in CRI's `ImageSpec` struct during image pulls from container runtimes.

- Do not detach volume if mount in progress ([#71145](https://github.com/kubernetes/kubernetes/pull/71145), [@gnufied](https://github.com/gnufied))
- The runtimeHandler field on the RuntimeClass resource now accepts the empty string. ([#69550](https://github.com/kubernetes/kubernetes/pull/69550), [@tallclair](https://github.com/tallclair))