- The default value for node-monitor-grace-period has been increased to 50s (earlier 40s) (Ref - https://github.com/kubernetes/kubernetes/issues/121793) ([#126287](https://github.com/kubernetes/kubernetes/pull/126287), [@devppratik](https://github.com/devppratik)) [SIG API Machinery,...

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

- 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))

  - 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...

* 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))

- 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),...

- 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))

  - 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))

- Added a new metric `webhook_fail_open_count` to monitor webhooks that fail to open. ([#107171](https://github.com/kubernetes/kubernetes/pull/107171), [@ltagliamonte-dd](https://github.com/ltagliamonte-dd))

- kubelet now allows the use of XFS quotas (on XFS and suitably configured ext4fs filesystems) to monitor storage consumption for ephemeral storage.  This method of monitoring consumption, which is currently available only for `emptyDir` volumes, is faster and more accurate than the old method of walking the filesystem tree. Note that it does not enforce limits, it only monitors consumption. To utilize this functionality, set the feature gate `LocalStorageCapacityIsolationFSQuotaMonitoring=true`....