## Changelog since v1.23.0-beta.0

## Changes by Kind

### API Change

- Add gRPC probe to Pod.Spec.Container.{Liveness,Readiness,Startup}Probe (#106463, @SergeyKanzhelev) [SIG API Machinery, Apps, CLI, Node and Testing]

* vSphere kube-up: Wait for cbr0 configuration to complete before setting up routes. ([#35232](https://github.com/kubernetes/kubernetes/pull/35232), [@kerneltime](https://github.com/kerneltime))
* Remove last probe time from replica sets ([#35199](https://github.com/kubernetes/kubernetes/pull/35199), [@kargakis](https://github.com/kargakis))

- If someone had the `ProbeTerminationGracePeriod` alpha feature enabled in 1.21, they should update/delete any workloads/pods with probe `terminationGracePeriods` < 1 before upgrading ([#103245](https://github.com/kubernetes/kubernetes/pull/103245), [@wzshiming](https://github.com/wzshiming))

* 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))

    * 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.

* Set route_localnet on nodes & masters in GCE ([#55004](https://github.com/kubernetes/kubernetes/pull/55004), [@ihmccreery](https://github.com/ihmccreery))
* Configurable liveness probe initial delays for etcd and kube-apiserver in GCE ([#57749](https://github.com/kubernetes/kubernetes/pull/57749), [@wojtek-t](https://github.com/wojtek-t))

* Flush conntrack state for removed/changed UDP Services ([#22573](https://github.com/kubernetes/kubernetes/pull/22573), [@freehan](https://github.com/freehan))
* Allow setting the Host header in a httpGet probe ([#24292](https://github.com/kubernetes/kubernetes/pull/24292), [@errm](https://github.com/errm))

* Fixed incomplete kubectl bash completion. ([#31333](https://github.com/kubernetes/kubernetes/pull/31333), [@xingzhou](https://github.com/xingzhou))
* Added liveness probe to Heapster service. ([#31878](https://github.com/kubernetes/kubernetes/pull/31878), [@mksalawa](https://github.com/mksalawa))

- 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...

- 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),...