- Fix control plane hosts rolling upgrade causing thundering herd of LISTs on etcd leading to control plane unavailability. ([#86430](https://github.com/kubernetes/kubernetes/pull/86430), [@wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery, Node and Testing]

    * Remove metadata agent config maps in favor of command line flags.
    * Update the metadata agent's liveness probe to a new /healthz handler.
    * Logging Agent Improvements
    * Bump logging agent version to 0.2-1.5.33-1-k8s-1.
    * Appropriately set log severity for k8s_container.
    * Fix detect exceptions plugin to analyze message field instead of log field.

* Audit logs might impact the API server performance and the latency of large request and response calls. The issue is observed under the following conditions: if `AdvancedAuditing` feature gate is enabled, which is the default case, if audit logging uses the log backend in JSON format, or if the audit policy records large API calls for requests or responses.

For more information, see [#51899](https://github.com/kubernetes/kubernetes/issues/51899).

- Migrated `pod-security-admission` to use [contextual logging](https://k8s.io/docs/concepts/cluster-administration/system-logs/#contextual-logging). ([#114471](https://github.com/kubernetes/kubernetes/pull/114471), [@Namanl2001](https://github.com/Namanl2001)) [SIG Apps and Auth]

### CLI Improvements
- The kubectl's api-resource command now has a `--sort-by` flag to sort resources by name or kind. ([#81971](https://github.com/kubernetes/kubernetes/pull/81971), [@laddng](https://github.com/laddng))

  Migrated the `PersistentVolumeClaim` protection controller (within `kube-controller-manager`) to use [contextual logging](https://k8s.io/docs/concepts/cluster-administration/system-logs/#contextual-logging).

* Upgrade Stackdriver Logging Agent addon image to 0.6-1.6.0-1 to use Fluentd v1.2. This provides nanoseconds timestamp granularity for logs. ([#70954](https://github.com/kubernetes/kubernetes/pull/70954), [@qingling128](https://github.com/qingling128))

* Fix garbage collection and resource quota when the controller-manager uses --leader-elect=false ([#57340](https://github.com/kubernetes/kubernetes/pull/57340), [@jmcmeek](https://github.com/jmcmeek))
* kube-apiserver: fixes loading of `--admission-control-config-file` containing AdmissionConfiguration apiserver.k8s.io/v1alpha1 config object ([#58441](https://github.com/kubernetes/kubernetes/pull/58441), [@liggitt](https://github.com/liggitt))

### Structured Logging in Kubelet

* Add a check for file size if the reading content returns empty ([#33976](https://github.com/kubernetes/kubernetes/pull/33976), [@jingxu97](https://github.com/jingxu97))
* Add a retry when reading a file content from a container ([#35560](https://github.com/kubernetes/kubernetes/pull/35560), [@jingxu97](https://github.com/jingxu97))