periodSeconds, successThreshold, failureThreshold
  * The new ReplicaSet API (Beta) in the Extensions API group is similar to
ReplicationController, but its [selector](http://kubernetes.io/docs/user-guide/labels/#label-selectors) is more general (supports set-based selector; whereas ReplicationController
only supports equality-based selector).
  * Scale subresource support is now expanded to ReplicaSets along with

- The validation of `replicas` field in the ReplicationController `/scale` subresource has been migrated to declarative validation.
  If the `DeclarativeValidation` feature gate is enabled, mismatches with existing validation are reported via metrics.

    *   The view role includes read permissions on poddisruptionbudget.policy resources.
*   RBAC rules can now match the same subresource on any resource using the form `*/(subresource)`. For example, `*/scale` matches requests to `replicationcontroller/scale`. ([#53722](https://github.com/kubernetes/kubernetes/pull/53722),[ @deads2k](https://github.com/deads2k))

* Fix premature return ([#49834](https://github.com/kubernetes/kubernetes/pull/49834), [@guoshimin](https://github.com/guoshimin))
* StatefulSet uses scale subresource when scaling in accord with ReplicationController, ReplicaSet, and Deployment implementations. ([#49168](https://github.com/kubernetes/kubernetes/pull/49168), [@crimsonfaith91](https://github.com/crimsonfaith91))

- Track ownership of scale subresource for all scalable resources i.e. Deployment, ReplicaSet, StatefulSet, ReplicationController, and Custom Resources. ([#98377](https://github.com/kubernetes/kubernetes/pull/98377), [@nodo](https://github.com/nodo)) [SIG API Machinery and Testing]

### Feature