- Simplied validation error message for invalid fields by removing redundant field name. ([#132513](https://github.com/kubernetes/kubernetes/pull/132513), [@xiaoweim](https://github.com/xiaoweim)) [SIG API Machinery, Apps, Auth, Node and Scheduling]

  If the `DeclarativeValidation` feature gate is enabled, mismatches with existing validation are reported via metrics.

  * Previously this would cause the command to fail regardless of whether or not the field was present in the object model
  * Now the command will succeed even if the sort-by field is missing from one or more of the objects

  `hostAliases` fields to mark the fields used as keys in those lists as either defaulted
  or required. ([#124553](https://github.com/kubernetes/kubernetes/pull/124553), [@pmalek](https://github.com/pmalek))

- The `metadata.clusterName` field is completely removed. This should not have any user-visible impact. ([#109602](https://github.com/kubernetes/kubernetes/pull/109602), [@lavalamp](https://github.com/lavalamp))

### API Change

* ACTION REQUIRED: The Node.Status.Volumes.Attached.DevicePath field is now unset for CSI volumes. Update any external controllers that depend on this field. ([#75799](https://github.com/kubernetes/kubernetes/pull/75799), [@msau42](https://github.com/msau42))...

- Add Probe-level terminationGracePeriodSeconds field ([#99375](https://github.com/kubernetes/kubernetes/pull/99375), [@ehashman](https://github.com/ehashman)) [SIG API Machinery, Apps, Node and Testing]

- Added etcd_object_count metrics for CustomResources. ([#65983](https://github.com/kubernetes/kubernetes/pull/65983), [@sttts](https://github.com/sttts))
- The OpenAPI version field will now be properly autopopulated without needing other OpenAPI fields present in generic API server code. ([#66411](https://github.com/kubernetes/kubernetes/pull/66411), [@DirectXMan12](https://github.com/DirectXMan12))

  - true/strict - perform validation and error the request on any invalid fields in the ojbect. It will attempt to perform server-side validation if it is enabled on the apiserver, otherwise it will fall back to client-side validation.
  - warn - perform server-side validation and warn on any invalid fields (but ultimately let the request succeed by dropping any invalid fields from the object). If validation is not available on the server, perform no validation.