- Improved how the API server responds to **list** requests where the response format negotiates to Protobuf. List responses in Protobuf are marshalled one element at the time, drastically reducing memory needed to serve large collections. Streaming list responses can be disabled via the `StreamingCollectionEncodingToProtobuf` feature gate. ([#129407](https://github.com/kubernetes/kubernetes/pull/129407), [@serathius](https://github.com/serathius)) [SIG API Machinery,...

- Fix kube-apiserver not to create default/kubernetes service endpoints before it reports readiness via the /healthz and therefore is ready to serve requests. Also early during startup old endpoints are remove which might be left over from a previously crashed kube-apiserver. ([#74668](https://github.com/kubernetes/kubernetes/pull/74668), [@sttts](https://github.com/sttts))

- The conformance tests:
  - Services should serve multiport endpoints from pods
  - Services should serve a basic endpoint from pods
  were only validating the API objects, not performing any validation on the actual Services implementation.

- The kube-apiserver will no longer serve APIs that should have been deleted in GA non-alpha levels.  Alpha levels will continue to serve the removed APIs so that CI doesn't immediately break. ([#96525](https://github.com/kubernetes/kubernetes/pull/96525), [@deads2k](https://github.com/deads2k)) [SIG API Machinery]

requests without a resourceVersion from the watch cache by default, as in <1.27 (disabling the change in #115096 by default). This mitigates the impact of an etcd watch bug (https://github.com/etcd-io/etcd/pull/17555). If the 1.27 change in #115096 to serve these requests from underlying storage is still desired despite the impact on watch stability, it can be re-enabled with a `WatchFromStorageWithoutResourceVersion` feature gate. ([#124006](https://github.com/kubernetes/kubernetes/pull/124006), [@s...

- Kubeadm: add the deprecated flag --port=0 to kube-controller-manager and kube-scheduler manifests to disable insecure serving. Without this flag the components by default serve (e.g. /metrics) insecurely on the default node interface (controlled by --address). Users that wish to override this behavior and enable insecure serving can pass a custom --port=X via kubeadm's "extraArgs" mechanic for these components. ([#92720]...

- Kubeadm: add the deprecated flag --port=0 to kube-controller-manager and kube-scheduler manifests to disable insecure serving. Without this flag the components by default serve (e.g. /metrics) insecurely on the default node interface (controlled by --address). Users that wish to override this behavior and enable insecure serving can pass a custom --port=X via kubeadm's "extraArgs" mechanic for these components. ([#92720]...

* InfluxDB cluster monitoring has been deprecated as part of the deprecation of Heapster. Instead, you may use the [metrics server](https://github.com/kubernetes-incubator/metrics-server). It's a simplified heapster that is able to gather and serve current metrics values. It provides the Metrics API that is used by `kubectl top`, and horizontal pod autoscaler. Note that it doesn't include some features of Heapster, such as short term metrics for graphs in kube-dashboard and dedicated push sinks,...

- Kube-apiserver: Previously persisted `CustomResourceDefinition` objects with an invalid whitespace-only `caBundle` could serve requests that did not require conversion. ([#132514](https://github.com/kubernetes/kubernetes/pull/132514), [@tiffanny29631](https://github.com/tiffanny29631))

- CustomResourceDefinition objects created with non-empty `caBundle` fields which are invalid or do not contain any certificates will not appear in discovery or serve endpoints until a valid `caBundle` is provided. Updates to CustomResourceDefinition are no longer allowed to transition a valid `caBundle` field to an invalid `caBundle` field, because this breaks serving of the existing CustomResourceDefinition. ...