- Introduce a new server run option 'shutdown-send-retry-after'. If true the HTTP Server will continue listening until all non longrunning request(s) in flight have been drained, during this window all incoming requests will be rejected with a status code `429` and a 'Retry-After' response header. ([#101257](https://github.com/kubernetes/kubernetes/pull/101257), [@tkashem](https://github.com/tkashem))

    an `Ingress` creation request to the Federation API Server. The
    Federation control system then creates and maintains a single
    global virtual IP to load balance incoming HTTP(S) traffic across
    some or all the registered clusters, across all regions. Google's
    GCE L7 LoadBalancer is the first supported implementation, and
	is available in this release.

### Other (Cleanup or Flake)

- Kube-apiserver: sets an upper-bound on the lifetime of idle keep-alive connections and time to read the headers of incoming requests ([#103958](https://github.com/kubernetes/kubernetes/pull/103958), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Node]

## Dependencies

### Added
_Nothing has changed._

be migrated at the current time using the official Kubernetes procedure.

1.6 will also default to protobuf encoding if using etcd3.  **This change is
irreversible.**  To rollback, you must restore from a backup made before the
protobuf/etcd3 switch, and any changes since the backup will be lost.  As 1.5
does not support protobuf encoding, if you roll back to 1.5 after upgrading to

* The Prometheus metrics for the kube-apiserver for tracking incoming API requests and latencies now return the subresource label for correctly attributing the type of API call. ([#46354](https://github.com/kubernetes/kubernetes/pull/46354), [@smarterclayton](https://github.com/smarterclayton))

### Other (Cleanup or Flake)

- Kube-apiserver: sets an upper-bound on the lifetime of idle keep-alive connections and time to read the headers of incoming requests ([#103958](https://github.com/kubernetes/kubernetes/pull/103958), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Node]

## Dependencies

### Added
_Nothing has changed._

### Changed

  - path definitions added a `pathType` field to allow indicating how the specified path should be matched against incoming requests. Valid values are `Exact`, `Prefix`, and `ImplementationSpecific` ([#88587](https://github.com/kubernetes/kubernetes/pull/88587), [@cmluciano](https://github.com/cmluciano)) [SIG Apps, Cluster Lifecycle and Network]

- `plugin_evaluation_total` metric supports prescore/score extension point.
  The metric doesn't get incremented when the prescore/score plugin has nothing to do with an incoming pod. ([#118025](https://github.com/kubernetes/kubernetes/pull/118025), [@AxeZhan](https://github.com/AxeZhan))

### Documentation

  private val headersReader = HeadersReader(socket.source)

  private val Response.isChunked: Boolean
    get() = "chunked".equals(header("Transfer-Encoding"), ignoreCase = true)

  private val Request.isChunked: Boolean
    get() = "chunked".equals(header("Transfer-Encoding"), ignoreCase = true)

  /**
   * Trailers received when the response body became exhausted.
   *

- `RequestedToCapacityRatioArgs` encoding is now strict ([#91603](https://github.com/kubernetes/kubernetes/pull/91603), [@pancernik](https://github.com/pancernik)) [SIG Scheduling]