- `sync_proxy_rules_latency_microseconds` -> `sync_proxy_rules_latency_seconds`
- `apiserver_request_count` -> `apiserver_request_total`
- `apiserver_request_latencies` -> `apiserver_request_latency_seconds`
- `apiserver_request_latencies_summary` -> `apiserver_request_latency_seconds`
- `apiserver_dropped_requests` -> `apiserver_dropped_requests_total`
- `etcd_helper_cache_hit_count` -> `etcd_helper_cache_hit_total`

- Deprecated prometheus request meta-metrics have been removed
 `http_request_duration_microseconds` `http_request_duration_microseconds_sum` `http_request_duration_microseconds_count`
 `http_request_size_bytes`
 `http_request_size_bytes_sum`
 `http_request_size_bytes_count`
 `http_requests_total, http_response_size_bytes`
 `http_response_size_bytes_sum`

    String INDEXER_WEBFS_MAX_DOCUMENT_REQUEST_SIZE = "indexer.webfs.max.document.request.size";

    /** The key of the configuration. e.g. 10000 */
    String INDEXER_DATA_MAX_DOCUMENT_CACHE_SIZE = "indexer.data.max.document.cache.size";

    /** The key of the configuration. e.g. 1048576 */
    String INDEXER_DATA_MAX_DOCUMENT_REQUEST_SIZE = "indexer.data.max.document.request.size";

  - `priority_level_request_count_samples` is replaced with `priority_level_request_utilization`, which samples every nanosecond rather than every millisecond; the old metric conveyed utilization despite its name.
  - `priority_level_request_count_watermarks` is removed.

- Updated `etcd` version to `3.5.8`. ([#117335](https://github.com/kubernetes/kubernetes/pull/117335), [@kkkkun](https://github.com/kkkkun))
- Updated apiserver metric `request_filter_duration_seconds` to include a 10s, 15s and 30s bucket.
Updated apiserver metric `request_wait_duration_seconds` to include a 15s bucket. ([#118945](https://github.com/kubernetes/kubernetes/pull/118945), [@andrewsykim](https://github.com/andrewsykim))

      - `kubeproxy_sync_proxy_rules_latency_microseconds` -> `kubeproxy_sync_proxy_rules_duration_seconds`
      - `apiserver_request_latencies` -> `apiserver_request_duration_seconds`
      - `apiserver_dropped_requests` -> `apiserver_dropped_requests_total`
      - `etcd_request_latencies_summary` -> `etcd_request_duration_seconds`
      - `apiserver_storage_transformation_latencies_microseconds ` -> `apiserver_storage_transformation_duration_seconds`

- Added a path `/header?key=` to `agnhost netexec` allowing one to view what the header value is of the incoming request.

  Ex:
  ```

- Removed the `GRPCContainerProbe` feature gate (the feature is stable and always enabled). ([#120248](https://github.com/kubernetes/kubernetes/pull/120248), [@pacoxu](https://github.com/pacoxu))
- Renamed `apiserver_request_body_sizes` metric to `apiserver_request_body_size_bytes`. ([#120503](https://github.com/kubernetes/kubernetes/pull/120503), [@dgrisonnet](https://github.com/dgrisonnet))

- Added kube-apiserver metrics: apiserver_current_inflight_request_measures and, when API Priority and Fairness is enable, windowed_request_stats. ([#91177](https://github.com/kubernetes/kubernetes/pull/91177), [@MikeSpreitzer](https://github.com/MikeSpreitzer)) [SIG API Machinery, Instrumentation and Testing]

* The behavior of the default handler for 404 requests fro the GCE Ingress load balancer is slightly modified in the sense that it now exports metrics using prometheus. The metrics exported include:  ([#79106](https://github.com/kubernetes/kubernetes/pull/79106), [@vbannai](https://github.com/vbannai))
    * - http_404_request_total  (the number of 404 requests handled)
    * - http_404_request_duration_ms (the amount of time the server took to respond in ms)