With Kubernetes 1.15 as beta, OpenAPI schemas are also published for CRDs, as long as their schemas are structural.

These changes are reflected in the following Kubernetes enhancements:

- Kubeadm: Fixed a bug where the PublicKeysECDSA feature gate was not respected when generating kubeconfig files. ([#125388](https://github.com/kubernetes/kubernetes/pull/125388), [@neolit123](https://github.com/neolit123))

    * It supports two modes:
        * CIDR range allocations done within the cluster that are then propagated out to the cloud provider.
        * Cloud provider managed IPAM that is then reflected into the cluster.
* Alpha list paging implementation ([#48921](https://github.com/kubernetes/kubernetes/pull/48921), [@smarterclayton](https://github.com/smarterclayton))

    * It supports two modes:
        * CIDR range allocations done within the cluster that are then propagated out to the cloud provider.
        * Cloud provider managed IPAM that is then reflected into the cluster.

- The getters for the field name and typeDescription of the Reflector struct were renamed. ([#128035](https://github.com/kubernetes/kubernetes/pull/128035), [@alexanderstephan](https://github.com/alexanderstephan)) [SIG API Machinery]

- Introduces new alpha functionality to the reflector, allowing user to enable API streaming.
  
  To activate this feature, users can set the `ENABLE_CLIENT_GO_WATCH_LIST_ALPHA` environmental variable.
  It is important to note that the server must support streaming for this feature to function properly.
  If streaming is not supported by the server, the reflector will revert to the previous method

- Kubeadm: add support for dry running `kubeadm...

- CPU limits are now respected for Windows containers. If a node is over-provisioned, no weighting is used, only limits are respected. ([#86101](https://github.com/kubernetes/kubernetes/pull/86101), [@PatrickLang](https://github.com/PatrickLang)) [SIG Node, Testing and Windows]

- Added validation to reject Pods using the `PodLevelResources` feature on Windows OS due to lack of support. The API server rejected Pods with pod-level resources and a `Pod.spec.os.name` targeting Windows. Kubelet on nodes running Windows also rejected Pods with pod-level resources at the admission phase. ([#133046](https://github.com/kubernetes/kubernetes/pull/133046), [@toVersus](https://github.com/toVersus)) [SIG Apps and Node]

- Kubeadm: fixed a regression where the JoinConfiguration.discovery.timeout was no longer respected and the value was always hardcoded to "5m" (5 minutes). ([#125481](https://github.com/kubernetes/kub...