- Kube-apiserver adds two new alpha metrics `conversion_webhook_request_total` and `conversion_webhook_duration_seconds` that allow users to monitor requests to CRD conversion webhooks, split by result, and failure_type (In case of failure). ([#118292](https://github.com/kubernetes/kubernetes/pull/118292), [@cchapla](https://github.com/cchapla)) [SIG API Machinery, Architecture...

* The webhook admission plugin now works even if the API server and the nodes are in two separate networks,for example, in GKE.
The webhook admission plugin now lets the webhook author use the DNS name of the service as the CommonName when generating the server cert for the webhook.
Action required:

    * New support for documenting **webhooks**, read the new docs here: <a href="https://fastapi.tiangolo.com/advanced/openapi-webhooks/" class="external-link" target="_blank">Advanced User Guide: OpenAPI Webhooks</a>.
    * Upgrade OpenAPI 3.1.0, this uses JSON Schema 2020-12.
    * Upgrade Swagger UI to version 5.x.x, that supports OpenAPI 3.1.0.

- `apiserver_admission_webhook_admission_duration_seconds` buckets have been expanded, 25s is now the largest bucket size to match the webhook default timeout. ([#115802](https://github.com/kubernetes/kubernetes/pull/115802), [@logicalhan](https://github.com/logicalhan)) [SIG API Machinery and Instrumentation]

- Added support for CEL expressions to `v1alpha1 AuthorizationConfiguration` webhook `matchConditions`. ([#121223](https://github.com/kubernetes/kubernetes/pull/121223), [@ritazh](https://github.com/ritazh))

  // GMSACredentialSpecName is the name of the GMSA credential spec to use.
  // +optional
  optional string gmsaCredentialSpecName = 1;

  // GMSACredentialSpec is where the GMSA admission webhook
  // (https://github.com/kubernetes-sigs/windows-gmsa) inlines the contents of the
  // GMSA credential spec named by the GMSACredentialSpecName field.
  // +optional
  optional string gmsaCredentialSpec = 2;

- Ignore context canceled from validate and mutate webhook ([#120019](https://github.com/kubernetes/kubernetes/pull/120019), [@divyasri537](https://github.com/divyasri537)) [SIG API Machinery]