- HPA controller exposes the following metrics from the kube-controller-manager. 
  - `metric_computation_duration_seconds`: The time(seconds) that the HPA controller takes to calculate one metric.

- `kube-proxy` in iptables mode will now have separate `sync_full_proxy_rules_duration_seconds`\nand
  `sync_partial_proxy_rules_duration_seconds` (in addition to the existing\n`sync_proxy_rules_duration_seconds`),
  giving better information about the duration of each \nsync type, rather than

* API server authentication now caches successful bearer token authentication results for a few seconds. ([#50258](https://github.com/kubernetes/kubernetes/pull/50258), [@liggitt](https://github.com/liggitt))

- A new kubelet metric `image_pull_duration_seconds` was added. The metric tracks the duration (in seconds) it takes for an image to be pulled, including the time spent in the waiting queue of image puller. The metric is broken down by bucketed image size. ([#121719](https://github.com/kubernetes/kubernetes/pull/121719), [@...

- Graduated the following kubelet resource metrics to **general availability**:
  - `container_cpu_usage_seconds_total`
  - `container_memory_working_set_bytes`
  - `container_start_time_seconds`
  - `node_cpu_usage_seconds_total`
  - `node_memory_working_set_bytes`
  - `pod_cpu_usage_seconds_total`
  - `pod_memory_working_set_bytes`
  - `resource_scrape_error`
  

- Deprecated the `apiserver_request_slo_duration_seconds` metric for v1.27 in favor of `apiserver_request_sli_duration_seconds` for naming consistency purposes with other SLI-specific metrics and to avoid any confusion between SLOs and SLIs. ([#112679](https://github.com/kubernetes/kubernetes/pull/112679), [@dgrisonnet](https://github.com/dgrisonnet))...