- Pod status updates faster when reacting on probe results. The first readiness probe will be called faster when startup probes succeeded, which will make Pod status as ready faster. ([#98376](https://github.com/kubernetes/kubernetes/pull/98376), [@matthyx](https://github.com/matthyx))

- Implemented logging and event recording for probe results with an `Unknown` status in the kubelet's prober module. This helped improve the diagnosis and monitoring of cases where container probes returned an `Unknown` result, enhancing the observability and reliability of health checks. ([#125901](https://github.com/kubernetes/kubernetes/pull/125901), [@jralmaraz](htt...

build:use_tar_archive_files --repo_env=USE_NVSHMEM_TAR_ARCHIVE_FILES=1
build:use_tar_archive_files --repo_env=USE_LLVM_TAR_ARCHIVE_FILES=1
build:use_tar_archive_files --repo_env=USE_MIRRORED_TAR_ARCHIVE_FILES=1

# Make Bazel not try to probe the host system for a C++ toolchain.
build:rbe_base --config=use_tar_archive_files
build:rbe_base --config=resultstore
build:rbe_base --repo_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1
build:rbe_base --define=EXECUTOR=remote

have both been migrated.

### gRPC Probes Graduate to Beta

With Kubernetes 1.24, the [gRPC probes functionality](https://github.com/kubernetes/enhancements/issues/2727)
has entered beta and is available by default. You can now [configure startup, liveness, and readiness probes](https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/#configure-probes) for your gRPC app

* azure: update disk lock logic per vm during attach/detach to allow concurrent updates for different nodes. ([#85115](https://github.com/kubernetes/kubernetes/pull/85115), [@aramase](https://github.com/aramase))
* Ensure health probes are created for local traffic policy UDP services on Azure ([#85327](https://github.com/kubernetes/kubernetes/pull/85327), [@nilo19](https://github.com/nilo19))

- Kubeadm: Switched to using the new etcd endpoints introduced in 3.5.11 - /livez (for liveness probe) and /readyz (for readyness and startup probe). With this change it is no longer possible to deploy a custom etcd version older than 3.5.11 with kubeadm 1.31. If so, please upgrade etcd to a supported version. ([#124465](https://github.com/kubernetes/kubernetes/pull/124465),...

    * Bump metadata agent version to 0.2-0.0.21-1.
    * Expand the metadata agent's access to all API groups.
    * 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.

* allow group impersonation ([#30803](https://github.com/kubernetes/kubernetes/pull/30803), [@deads2k](https://github.com/deads2k))
* Always return command output for exec probes and kubelet RunInContainer ([#30731](https://github.com/kubernetes/kubernetes/pull/30731), [@ncdc](https://github.com/ncdc))

* addon-resizer flapping behavior was removed. ([#46850](https://github.com/kubernetes/kubernetes/pull/46850), [@x13n](https://github.com/x13n))
* Change default `httpGet` probe `User-Agent` to `kube-probe/<version major.minor>` if none specified, overriding the default Go `User-Agent`. ([#47729](https://github.com/kubernetes/kubernetes/pull/47729), [@paultyng](https://github.com/paultyng))

## Changelog since v1.18.18

## Changes by Kind

### API Change

- We have added a new Priority & Fairness rule that exempts all probes (/readyz, /healthz, /livez) to prevent 
  restarting of "healthy" kube-apiserver instance(s) by kubelet. ([#101114](https://github.com/kubernetes/kubernetes/pull/101114), [@tkashem](https://github.com/tkashem)) [SIG API Machinery]