* Adds a metric apiserver_request_error_total to kube-apiserver. This metric tallies the number of request_errors encountered by verb, group, version, resource, subresource, scope, component, and code. ([#84780](https://github.com/kubernetes/kubernetes/pull/84780), [@RainbowMango](https://github.com/RainbowMango))

- Registered metric `apiserver_request_body_size_bytes` to track the size distribution of requests by `resource` and `verb`. ([#120474](https://github.com/kubernetes/kubernetes/pull/120474), [@YaoC](https://github.com/YaoC)) [SIG API Machinery and Instrumentation]

- Pod spread constraints have been added in alpha. You can use these constraints to control how Pods are spread across the cluster among failure-domains. ([#77327](https://github.com/kubernetes/kubernetes/pull/77327), [#77760](...

### Feature

- A new client side metric `rest_client_request_retries_total` has been added that tracks the number of retries sent to the server, partitioned by status code, verb and host ([#108396](https://github.com/kubernetes/kubernetes/pull/108396), [@tkashem](https://github.com/tkashem))

    * `kubectl delete node/<nodeName>`
    * or grant self-deletion permission explicitly:
        * `kubectl create clusterrole self-deleting-nodes --verb=delete --resource=nodes`
        * `kubectl create clusterrolebinding self-deleting-nodes --clusterrole=self-deleting-nodes --group=system:nodes`

- Kube-apiserver: `DELETECOLLECTION API` requests are now recorded in metrics with the correct verb. ([#113133](https://github.com/kubernetes/kubernetes/pull/113133), [@sxllwx](https://github.com/sxllwx))

* Adds a metric apiserver_request_error_total to kube-apiserver. This metric tallies the number of request_errors encountered by verb, group, version, resource, subresource, scope, component, and code. ([#84777](https://github.com/kubernetes/kubernetes/pull/84777), [@RainbowMango](https://github.com/RainbowMango))