- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates on disk and in kubeconfig files. ([#106924](https://github.com/kubernetes/kubernetes/pull/106924), [@neolit123](https://gi...

  - The requested name does not match the set of authorized names (x509.HostnameError)
  - The error surfaced after attempting a connection contains one of the substrings: "certificate is not trusted" or "certificate signed by unknown authority" ([#120767](https://github.com/kubernetes/kubernetes/pull/120767), [@MadhavJivrajani](https://github.com/MadhavJivrajani)) [SIG Architecture and Cloud Provider]

  `sync_partial_proxy_rules_duration_seconds` (in addition to the existing\n`sync_proxy_rules_duration_seconds`),
  giving better information about the duration of each \nsync type, rather than
  only giving a weighted average of the two sync types together. ([#117787](https://github.com/kubernetes/kubernetes/pull/117787), [@danwinship](https://github.com/danwinship))
- `kubeadm`: added a new "kubeadm config validate" command that can be used to

### Signing Release Artifacts

Release artifacts are [signed](https://github.com/kubernetes/enhancements/issues/3031) using [cosign](https://github.com/sigstore/cosign)
signatures
and there is experimental support for [verifying image signatures](https://kubernetes.io/docs/tasks/administer-cluster/verify-signed-images/).

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates on disk and in kubeconfig files. ([#106925](https://github.com/kubernetes/kubernetes/pull/106925), [@neolit123](https://gi...

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates on disk and in kubeconfig files. ([#106926](https://github.com/kubernetes/kubernetes/pull/106926), [@neolit123](https://gi...

  - The requested name does not match the set of authorized names (x509.HostnameError)
  - The error surfaced after attempting a connection contains one of the substrings: "certificate is not trusted" or "certificate signed by unknown authority" ([#120765](https://github.com/kubernetes/kubernetes/pull/120765), [@MadhavJivrajani](https://github.com/MadhavJivrajani)) [SIG Architecture and Cloud Provider]

- Addressed an issue where a JWT authenticator set up via `--authentication-config` would encounter failures in verifying tokens not signed with RS256. ([#123282](https://github.com/kubernetes/kubernetes/pull/123282), [@enj](https://github.com/enj))

    - `apiserver_flowcontrol_demand_seats_high_watermark`: High watermark, over last adjustment period, of demand_seats
    - `apiserver_flowcontrol_demand_seats_average`: Time-weighted average, over last adjustment period, of demand_seats
    - `apiserver_flowcontrol_demand_seats_stdev`: Time-weighted standard deviation, over last adjustment period, of demand_seats
    - `apiserver_flowcontrol_demand_seats_smoothed`: Smoothed seat demands

  - The requested name did not match the set of authorized names (`x509.HostnameError`)
  - The error surfaced after attempting a connection contained one of the substrings: "certificate is not trusted" or "certificate signed by unknown authority". ([#120736](https://github.com/kubernetes/kubernetes/pull/120736), [@MadhavJivrajani](https://github.com/MadhavJivrajani))