- Client-go: Optimized leaders renewing leases by updating leader lock optimistically without getting the record from the API server first. Also, a new metric `leader_election_slowpath_total` was added to allow users to monitor how many leader elections are updated non-optimistically.
   ([#122069](https://github.com/kubernetes/kubernetes/pull/122069), [@linxiulei](https://github.com/linxiulei))

    * Add ABRT support. ([#105](https://github.com/kubernetes/node-problem-detector/pull/105), [@juliusmilan](https://github.com/juliusmilan))

    * Add a docker image corruption problem detection in the default docker monitor config. ([#117](https://github.com/kubernetes/node-problem-detector/pull/117), [@ajitak](https://github.com/ajitak))

  * Upgrade CAdvisor to v0.26.1. New features added:

    * Add Docker overlay2 storage driver support.

* Increase waiting time (120s) for docker startup in health-monitor.sh ([#54099](https://github.com/kubernetes/kubernetes/pull/54099), [@dchen1107](https://github.com/dchen1107))

ner) throws Exception; } org/junit/runner/notification/SynchronizedRunListe.class package org.junit.runner.notification; final synchronized class SynchronizedRunListe extends RunListener { private final RunListener listener; private final Object monitor; void SynchronizedRunListe(RunListener, Object); public void testRunStarted(org.junit.runner.Description) throws Exception; public void testRunFinished(org.junit.runner.Result) throws Exception; public void testSuiteStarted(org.junit.runner.Description)...

  - By default, injected tokens are given an extended lifetime so they remain valid even after a new refreshed token is provided. The metric `serviceaccount_stale_tokens_total` can be used to monitor for workloads that are depending on the extended lifetime and are continuing to use tokens even after a refreshed token is provided to the container. If that metric indicates no existing workloads are depending on extended lifetimes, injected token...

* Include CRD for BGPConfigurations, needed for calico 2.x to 3.x upgrade. ([#71868](https://github.com/kubernetes/kubernetes/pull/71868), [@satyasm](https://github.com/satyasm))
* On GCI, NPD starts to monitor kubelet, docker, containerd crashlooping, read-only filesystem and corrupt docker overlay2 issues. ([#71522](https://github.com/kubernetes/kubernetes/pull/71522), [@wangzhen127](https://github.com/wangzhen127))

- If BoundServiceAccountTokenVolume is enabled, cluster admins can use metric `serviceaccount_stale_tokens_total` to monitor workloads that are depending on the extended tokens. If there are no such workloads, turn off extended tokens by starting `kube-apiserver` with flag `--service-account-extend-token-expiration=false` ([#96273](https://github.com/kubernetes/kubernetes/pull/96273),...

  - go_sched_latencies_seconds ([#111910](https://github.com/kubernetes/kubernetes/pull/111910), [@tosi3k](https://github.com/tosi3k))
- Added new metric `job_controller_terminated_pods_tracking_finalizer` which can be used to monitor whether the job controller is removing Pod finalizers from terminated Pods after accounting them in Job status. ([#113176](https://github.com/kubernetes/kubernetes/pull/113176), [@alculquicondor](https://github.com/alculquicondor))

* kubeadm: use kubeconfig flag instead of kubeconfig-dir on init phase bootstrap-token ([#71803](https://github.com/kubernetes/kubernetes/pull/71803), [@yagonobre](https://github.com/yagonobre))
* On GCI, NPD starts to monitor kubelet, docker, containerd crashlooping, read-only filesystem and corrupt docker overlay2 issues. ([#71522](https://github.com/kubernetes/kubernetes/pull/71522), [@wangzhen127](https://github.com/wangzhen127))

- Add three metrics to the job controller to monitor if a job works in healthy condition.
  `IndexedJob` has been promoted to Beta. ([#101292](https://github.com/kubernetes/kubernetes/pull/101292), [@AliceZhang2016](https://github.com/AliceZhang2016))