improvements in the 1.13 release.  A new alpha feature is introduced to improve the mechanism that nodes heartbeat back to the control plane.  The `NodeLease` feature results in the node using a `Lease` resource in the `kube-node-lease` namespace that is renewed periodically.  The `NodeStatus` that was used previously to heartbeat back to the control plane is only updated when it changes.  This reduces load on the control plane for large clusters. The Kubelet plugin registration mechanism, which enables automatic...

### Cluster Lifecycle

- The `NodeConfiguration` kind in the kubeadm v1alpha2 API has been renamed `JoinConfiguration` in v1alpha3 ([#65951](https://github.com/kubernetes/kubernetes/pull/65951), [@luxas](https://github.com/luxas)) Courtesy of SIG Cluster Lifecycle

  also supported using "kubeadm alpha certs renew", but not switching between the RSA and
  ECDSA algorithms on the fly or during upgrades. ([#86953](https://github.com/kubernetes/kubernetes/pull/86953), [@rojkov](https://github.com/rojkov)) [SIG API Machinery, Auth and Cluster Lifecycle]

on a node host or move it to a safe location. `kubadm certs renew` will renew the certificate in `super-admin.conf` to one year if the file exists; if it does not exist a "MISSING" note will be printed. `kubeadm upgrade apply` for this release will migrate this particular node to the two file setup. Subsequent kubeadm releases will continue to optionally renew the certificate in `super-admin.conf` if the file exists on disk and if renew on upgrade is not disabled. `kubeadm join --control-plane` will...

* Some field names in the Kubelet's now v1beta1 config API differ from the v1alpha1 API: for example, PodManifestPath is renamed to StaticPodPath, ManifestURL is renamed to StaticPodURL, and ManifestURLHeader is renamed to StaticPodURLHeader. Users should focus on switching to the v1beta1 API. ([#60314](https://github.com/kubernetes/kubernetes/pull/60314), [@mtaufen](https://github.com/mtaufen))

Renamed FeatureGate RequestManagement to APIPriorityAndFairness.  This feature gate is an alpha and has not yet been associated with any actual functionality. ([#85260](https://github.com/kubernetes/kubernetes/pull/85260), [@MikeSpreitzer](https://github...

  - Rename `PreemptionByKubeScheduler` to `PreemptionByScheduler` ([#114623](https://github.com/kubernetes/kubernetes/pull/114623), [@Huang-Wei](https://github.com/Huang-Wei))
- API: resource.k8s.io/v1alpha1.PodScheduling was renamed to resource.k8s.io/v1alpha2.PodSchedulingContext. ([#116556](https://github.com/kubernetes/kubernetes/pull/116556), [@pohly](https://github.com/pohly)) [SIG API Machinery, Apps, Auth, CLI, Node, Scheduling and Testing]

the entries. Added absentNodesStatus, which informs the status of nodes that are absent in the map. For developers of out-of-tree PostFilter plugins, ensure to update the usage of NodeToStatusMap. Additionally, NodeToStatusMap should eventually be renamed to NodeToStatusReader. ([#126022](https://github.com/kubernetes/kubernetes/pull/126022), [@macsko](https://github.com/macsko)) [SIG Node, Scheduling, and Testing]

- A new /resize subresource was added to request pod resource resizing....

 - Renamed `UpdatePodTolerations` action type to `UpdatePodToleration`.