KEPs or supporting documentation, please reference a specific commit and avoid
  linking directly to the master branch. This ensures that links reference a
  specific point in time, rather than a document that may change over time.
  
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focused on stability and performance 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...

- Kube-apiserver now maintains a Lease object to identify itself: 
  - The feature is under feature gate `APIServerIdentity`. 
  - Two flags are added to kube-apiserver: `identity-lease-duration-seconds`, `identity-lease-renew-interval-seconds` ([#95533](https://github.com/kubernetes/kubernetes/pull/95533), [@roycaihw](https://github.com/roycaihw)) [SIG API Machinery]

* Updates Fluentd to 1.3.2 & added filter_parser  ([#71180](https://github.com/kubernetes/kubernetes/pull/71180), [@monotek](https://github.com/monotek))
* The leaderelection package allows the lease holder to release its lease when the calling context is cancelled. This allows ([#71490](https://github.com/kubernetes/kubernetes/pull/71490), [@smarterclayton](https://github.com/smarterclayton))

### Feature

- Add flag --lease-max-object-size and metric etcd_lease_object_counts for kube-apiserver to config and observe max objects attached to a single etcd lease. ([#97480](https://github.com/kubernetes/kubernetes/pull/97480), [@lingsamuel](https://github.com/lingsamuel)) [SIG API Machinery, Instrumentation and Scalability]

#### kubelet:
- `--enable-cadvisor-json-endpoints` is now disabled by default. If you need access to the cAdvisor v1 Json API please enable it explicitly in the kubelet command line. Please note that this flag was deprecated in 1.15 and will be removed in 1.19. ([#87440](https://github.com/kubernetes/kubernetes/pull/87440), [@dims](https://github.com/dims)) [SIG Instrumentation, Node and Testing]

  KEPs or supporting documentation, please reference a specific commit and avoid
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  Please use the following format for linking documentation:

  * deleteOptions.orphanDependents is going to be deprecated in 1.7. Please use deleteOptions.propagationPolicy instead.

### kubeadm

* kube-apiserver: the default `--endpoint-reconciler-type` is now `lease`. The `master-count` endpoint reconciler type is deprecated and will be removed in 1.13. ([#63383](https://github.com/kubernetes/kubernetes/pull/63383), [@liggitt](https://github.com/liggitt))

- Apimachinery/clock: This deletes the apimachinery/clock package. Please use k8s.io/utils/clock instead. ([#109752](https://github.com/kubernetes/kubernetes/pull/109752), [@MadhavJivrajani](https://github.com/MadhavJivrajani)) [SIG API Machinery]