- Single static pod files and pod files from http endpoints cannot be larger than 10 MB. HTTP probe payloads are now truncated to 10KB. ([#82669](https://github.com/kubernetes/kubernetes/pull/82669), [@rphillips](https://github.com/rphillips))

## 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]

- github.com/prometheus/common: [v0.37.0 → v0.44.0](https://github.com/prometheus/common/compare/v0.37.0...v0.44.0)
- github.com/prometheus/procfs: [v0.8.0 → v0.10.1](https://github.com/prometheus/procfs/compare/v0.8.0...v0.10.1)
- github.com/seccomp/libseccomp-golang: [f33da4d → v0.10.0](https://github.com/seccomp/libseccomp-golang/compare/f33da4d...v0.10.0)

* 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.

- Fixed an issue where kubelet does not set case-insensitive headers for http probes. (#117182, @dddddai) ([#117324](https://github.com/kubernetes/kubernetes/pull/117324), [@dddddai](https://github.com/dddddai)) [SIG API Machinery, Apps and Node]

- 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))

Kubernetes now registers metadata.hostname as node name for OpenStack nodes, eliminating a problem with invalid node names. ([#58502](https://github.com/kubernetes/kubernetes/pull/58502), [@dixudx](https://github.com/dixudx))

* Authentication information for OpenStack cloud provider can now be specified as environment variables. When we convert the OpenStack cloud provider to run in an external process, we can now use the kubernetes Secrets capability to inject the OS_* variables. This way...

#### **RBAC**

*   New permissions have been added to default RBAC roles ([#52654](https://github.com/kubernetes/kubernetes/pull/52654),[ @liggitt](https://github.com/liggitt)):
    *   The default admin and edit roles now include read/write permissions
    *   The view role includes read permissions on poddisruptionbudget.policy resources.

* Kubelet now exposes a new endpoint, `/metrics/probes`, which exposes a Prometheus metric containing the liveness and/or readiness probe results for a container. ([#61369](https://github.com/kubernetes/kubernetes/pull/61369), [@rramkumar1](https://github.com/rramkumar1))

### SIG Network