- `kubeadm`: added a new "kubeadm config validate" command that can be used to
  validate any input config file. Use the `--config` flag to pass a config file
  to it. See the command `--help` screen for more information. As a result of adding
  this new command, enhance the validation capabilities of the existing "kubeadm

- Add flag --lease-max-object-size and metric etcd_lease_object_counts for kube-apiserver to config and observe max objects attached to a single etcd lease. ([#97480](https://github.com/kubernetes/kubernetes/pull/97480), [@lingsamuel](https://github.com/lingsamuel)) [SIG API Machinery, Instrumentation and Scalability]

## Changelog since v1.8.14

### Action Required

* ACTION REQUIRED: Kubernetes JSON deserializer is now case-sensitive to restore compatibility with pre-1.8 servers. If your config files contains fields with wrong case, the config files will be now invalid. ([#65410](https://github.com/kubernetes/kubernetes/pull/65410), [@nikhita](https://github.com/nikhita))

### Other notable changes

_hash_status_last_timestamp_seconds`, `apiserver_encryption_config_controller_automatic_reload_failures_total`, `apiserver_encryption_config_controller_automatic_reload_success_total`, `apiserver_encryption_config_controller_automatic_reload_last_timestamp_seconds`.
  
  Fixed bug to surface events for the following metrics: `apiserver_encryption_config_controller_automatic_reload_failures_total`, `apiserver_encryption_config_controller_automatic_reload_last_timestamp_seconds`, `apiser...

- KMS: added validation for duplicate kms config name when auto reload is enabled. If you enabled automatic reload of encryption configuration with API server flag `--encryption-provider-config-automatic-reload`, ensure all the KMS provider names (v1 and v2) in the encryption configuration...