### 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]

    * --alpha-endpoint-reconciler-type=(master-count, lease, none) (default
    * "master-count"). The original reconciler is 'master-count'. The 'lease'
    * reconciler uses the storageapi and a TTL to keep alive an endpoint within the
    * `kube-apiserver-endpoint` storage namespace. The 'none' reconciler is a noop

- `client-go`: fixed the wait time for trying to acquire the leader lease ([#114872](https://github.com/kubernetes/kubernetes/pull/114872), [@Iceber](https://github.com/Iceber))
- `etcd`: Updated to `v3.5.7` ([#115310](https://github.com/kubernetes/kubernetes/pull/115310), [@mzaian](https://github.com/mzaian))

* kubectl port-forward now allows using resource name (e.g., deployment/www) to select a matching pod, as well as the use of --pod-running-timeout to wait until at least one pod is running. ([#59705](https://github.com/kubernetes/kubernetes/pull/59705), [@phsiao](https://github.com/phsiao))

- kubelet: Users can now enable the alpha NodeLease feature gate to have the Kubelet create and periodically renew a Lease in the kube-node-lease namespace. The lease duration defaults to 40s, and can be configured via the kubelet.config.k8s.io/v1beta1.KubeletConfiguration's NodeLeaseDurationSeconds field. ([#66257](https://github.com/kubernetes/kubernetes/pull/66257), [@mtaufen](https://github.com/mtaufen))...

- The `Should recreate evicted statefulset` conformance [test]( https://github.com/kubernetes/kubernetes/blob/master/test/e2e/apps/statefulset.go) fails because `Pod ss-0 expected to be re-created at least once`. This was caused by the `Predicate PodFitsHostPorts failed` scheduling error. The root cause was a host port conflict for port `21017`. This port was in-use as an ephemeral port by another application running on the node. This will be looked...

updates to bypass a Validating Admission Webhook. You are only affected
by this vulnerability if you run a Validating Admission Webhook for Nodes
that denies admission based at least partially on the old state of the
Node object.

**Note**: This only impacts validating admission plugins that rely on old
values in certain fields, and does not impact calls from kubelets that go

`Initializers` admission plugin is enabled.([#51436](https://github.com/kubernetes/kubernetes/pull/51436))

* [Action required] The validation rule for metadata.initializers.pending[x].name is tightened. The initializer name must contain at least three segments, separated by dots. You can create objects with pending initializers and not rely on the API server to add pending initializers according to `initializerConfiguration`. If you do so, update the initializer name in the existing objects...

- `wait.PollUntilContextTimeout` function, if immediate is true, the condition
  will be invoked before waiting and guarantees that the condition is invoked at
  least once, regardless of whether the context has been cancelled. ([#118686](https://github.com/kubernetes/kubernetes/pull/118686), [@aojea](https://github.com/aojea))

### Other (Cleanup or Flake)

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...