1. If you experienced problems with Services not syncing to iptables correctly, you can disable the feature by passing `--feature-gates=MinimizeIPTablesRestore=false` to kube-proxy (and file a bug if this fixes it). (This might also be detected by seeing the value of kube-proxy's `sync_proxy_rules_iptables_partial_restore_failures_total` metric rising.)

CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

- One new field "InternalTrafficPolicy" in Service is added.
  It specifies if the cluster internal traffic should be routed to all endpoints or node-local endpoints only.
  "Cluster" routes internal traffic to a Service to all endpoints.
  "Local" routes traffic to node-local endpoints only, and traffic is dropped if no node-local endpoints are ready.

-->
Fixes #

#### Special notes for your reviewer:

#### Does this PR introduce a user-facing change?
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least one of the following places: within a NOTICE text file distributed as 
part of the Derivative Works; within the Source form or documentation, if 
provided along with the Derivative Works; or, within a display generated by 
the Derivative Works, if and wherever such third-party notices normally 
appear. The contents of the NOTICE file are for informational purposes only 

          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,
          within a display generated by the Derivative Works, if and
          wherever such third-party notices normally appear. The contents
          of the NOTICE file are for informational purposes only and

          * 'node.kubernetes.io/network-unavailable=:NoSchedule' if NetworkUnavailable is true
          * 'node.kubernetes.io/disk-pressure=:NoSchedule' if DiskPressure is true
          * 'node.kubernetes.io/memory-pressure=:NoSchedule' if MemoryPressure is true
          * 'node.kubernetes.io/out-of-disk=:NoSchedule' if OutOfDisk is true

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

  - if more than one QueueingHintFn returns QueueImmediately, it queues Pod to activeQ.
  - If no QueueingHintFn returns QueueImmediately and more than one plugin returns QueueAfterBackoff, it queues Pod to backoffQ if Pod is backing off, or to activeQ if Pod's backoff has already finished.
  - If all QueueingHintFn return QueueSkip, it puts this pod back to the unschedulable pod pool

          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,
          within a display generated by the Derivative Works, if and
          wherever such third-party notices normally appear. The contents
          of the NOTICE file are for informational purposes only and