- Client-go: Clients can request protobuf and json and correctly negotiate with the server for JSON for CRD objects, allowing all client libraries to request protobuf if it is available.  If an error occurs negotiating a watch with the server, the error is immediately return by the client `Watch()` method instead of being sent as an `Error`...

### Feature

WebhookConfiguration` so that webhooks can explicitly register as having dry-run support. If a dry-run request is made on a resource that triggers a non dry-run supporting webhook, the request will be completely rejected, with "400: Bad Request". Additionally, a new field is being added to the `admission.k8s.io/v1beta1.AdmissionReview` API object, exposing to webhooks whether or not the request being reviewed is a dry-run. ([#66936](https://github.com/kubernetes/kubernetes/pull/66936), [@jennybu...

  - A `create` or `update` API request with duplicate items in a keyed list no longer wipes out managedFields. Examples include env var entries with the same name, or port entries with the same containerPort in a pod spec.

should eventually be renamed to NodeToStatusReader. ([#126022](https://github.com/kubernetes/kubernetes/pull/126022), [@macsko](https://github.com/macsko)) [SIG Node, Scheduling, and Testing]

- A new /resize subresource was added to request pod resource resizing. Update your k8s client code to utilize the /resize subresource for Pod resizing operations. ([#128266](https://github.com/kubernetes/kubernetes/pull/128266), [@AnishShah](https://github.com/AnishShah)) [SIG API Machinery, Apps,...

- If the user specifies an invalid timeout in the request URL, the request will be aborted with an HTTP 400.

	    * The new metrics are:

	    * cloudprovider_gce_api_request_duration_seconds{request, region, zone}

	    * cloudprovider_gce_api_request_errors{request, region, zone}

	    * request is the specific function that is used.

	    * region is the target region (Will be "<n/a>" if not applicable)

        * At Request audit level or higher, an annotation with key "patch.webhook.admission.k8s.io/round_{round idx}_index_{order idx}" get logged with the JSON payload logging the patch sent by a webhook for given request.

- Kube-apiserver: ensures the namespace of objects sent to admission webhooks matches the request namespace. Previously, objects without a namespace set would have the request namespace populated after mutating admission, and objects with a namespace that did not match the request namespace would be rejected after admission. ([#94637](https://github.com/kubernetes/kubernetes/pull/94637), [@liggitt](https://github.com/liggitt))

- If the user specifies an invalid timeout in the request URL, the request will be aborted with an HTTP 400.