* kube-apiserver: the OpenID Connect authenticator can now verify ID Tokens signed with JOSE algorithms other than RS256 through the --oidc-signing-algs flag. ([#58544](https://github.com/kubernetes/kubernetes/pull/58544), [@ericchiang](https://github.com/ericchiang))

* The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane"...

* API server authentication now caches successful bearer token authentication results for a few seconds. ([#50258](https://github.com/kubernetes/kubernetes/pull/50258), [@liggitt](https://github.com/liggitt))

- The alpha feature `ServiceAccountIssuerDiscovery` enables publishing OIDC discovery information and service account token verification keys at `/.well-known/openid-configuration` and `/openid/v1/jwks` endpoints by API servers configured to issue service account tokens. ([#80724](https://github.com/kubernetes/kubernetes/pull/80724), [@cceckman](https://github.com/cceckman)) [SIG API Machinery, Auth, Cluster Lifecycle and Testing]...

* Laid the groundwork for OIDC distributed claims handling in the apiserver authentication token checker. A distributed claim allows the OIDC provider to delegate a claim to a separate URL. ([ref](http://openid.net/specs/openid-connect-core-1_0.html#AggregatedDistributedClaims)). ([#63213](https://github.com/kubernetes/kubernetes/pull/63213), [@filmil](https://github.com/filmil))

  
  kubelet also ignores an error during opening `/dev/kmsg`.
  This feature gate also allows kube-proxy to ignore an error during setting `RLIMIT_NOFILE`.
  

- Fixed detaching CSI volumes from nodes when a CSI driver name has prefix "csi-". ([#107025](https://github.com/kubernetes/kubernetes/pull/107025), [@jsafrane](https://github.com/jsafrane))
- Fixed duplicate port opening in kube-proxy when `--nodeport-addresses` is empty. ([#107413](https://github.com/kubernetes/kubernetes/pull/107413), [@tnqn](https://github.com/tnqn))

    * to enable, kube-proxy must be have the following flags:
    * --proxy-mode=ipvs
    * --cluster-cidrs=<cidr>,<cidr>
* The apiserver now uses http/1.1 to communicate with admission webhooks, opening multiple connections to satisfy concurrent requests, and allowing spreading requests across multiple backing pods. ([#82090](https://github.com/kubernetes/kubernetes/pull/82090), [@liggitt](https://github.com/liggitt))

Since these new workflows don’t require any new cluster features, they’re available for experimentation with your existing clusters via `kubectl alpha debug`. We’d love to hear your feedback on debugging with `kubectl`. Reach us by opening an issue, visiting [#sig-cli](https://kubernetes.slack.com/messages/sig-cli) or commenting on enhancement [#1441](https://features.k8s.io/1441).

### Structured logging

### Auth

- Fixed OpenID Connect (OIDC) token refresh when the client secret contains a special character. ([#76914](https://github.com/kubernetes/kubernetes/pull/76914), [@tsuna](https://github.com/tsuna))