### **Instrumentation**
#### Core Metrics API
* [alpha] Introduces a lightweight monitoring component for serving the core resource metrics API used by the Horizontal Pod Autoscaler and other components ([kubernetes/features#271](https://github.com/kubernetes/enhancements/issues/271))


### **Internationalization**

  It is possible that this will cause problems with some third-party components
  that improperly depended on those rules. If this affects you, you can run
  `kubelet` with `--feature-gates=IPTablesOwnershipCleanup=false`, but a bug should also be filed against the third-party component. ([#114472](https://github.com/kubernetes/kubernetes/pull/114472), [@danwinship](https://github.com/danwinship))

- Component owner can configure the allowlist of metric label with flag '--allow-metric-labels'. ([#99385](https://github.com/kubernetes/kubernetes/pull/99385), [@YoyinZyc](https://github.com/YoyinZyc)) [SIG API Machinery, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation and Release]

either no local stack frame or no function calls,
the only requirement is to define a Go prototype for the function
in a Go source file in the same package. The name of the assembly
function must not contain the package name component (for example,
function <code>Syscall</code> in package <code>syscall</code> should
use the name <code>·Syscall</code> instead of the equivalent name
<code>syscall·Syscall</code> in its <code>TEXT</code> directive).

- Component-base/logs: when compiled with Go >= 1.21, component-base will automatically configure the slog default logger together with initializing klog. ([#120696](https://github.com/kubernetes/kubernetes/pull/120696), [@pohly](https://github.com/pohly)) [SIG API Machinery, Architecture,...

### Cluster Lifecycle

- Added to `MutableFeatureGate` the ability to override the default setting of feature gates, to allow default-enabling a feature on a component-by-component basis instead of for all affected components simultaneously. ([#122647](https://github.com/kubernetes/kubernetes/pull/122647), [@benluddy](https://github.com/benluddy))

This API provided status of etcd, kube-scheduler, and kube-controller-manager components, but only worked when those components were local to the API server, and when kube-scheduler and kube-controller-manager exposed unsecured health endpoints. Instead of this API, etcd health is included in the kube-apiserver health check and kube-scheduler/kube-controller-manager health checks can be made directly against those components' health endpoints. ([#93570](https://github.com/kubernetes/kubernetes/pull/93570),...

packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that
Major Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form.  A
"Major Component", in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system

- kubeadm: all master components are now exclusively relying on the `PriorityClassName` pod spec for annotating them as cluster critical components. Since `scheduler.alpha.kubernetes.io/critical-pod` annotation is no longer supported by Kubernetes 1.14 this annotation is no longer added to master components. ([#73857](https://github.com/kubernetes/kubernetes/pull/73857), [@ereslibre](https://github.com/ereslibre))...