**Affected Versions**:

### Instrumentation

* GCE: Internal load balancer IPs are now reserved during service sync to prevent losing the address to another service. ([#51055](https://github.com/kubernetes/kubernetes/pull/51055), [@nicksardo](https://github.com/nicksardo))

- Sync node status during kubelet node shutdown.
  Adds an pod admission handler that rejects new pods when the node is in progress of shutting down. ([#98005](https://github.com/kubernetes/kubernetes/pull/98005), [@wzshiming](https://github.com/wzshiming)) [SIG Node]

    * DualStack:
    * => IPv4 BackendPool name == clusterName
    * => IPv6 BackendPool name == <clusterName>-IPv6
    * This result into:
    * - clusters moving from IPv4 to duakstack will require no changes
    * - clusters moving from IPv6 (while not seen in the wild, we can not rule out their existence) to dualstack will require deleting backend pools (the reconciler will take care of creating correct backendpools)

  * You can find out what taints you have in place on a node while you are still running Kubernetes 1.5 by doing `kubectl describe node <node name>`; the `Taints` section will show the taints you have in place. To see the taints that were created under 1.5 when you are running 1.6, do `kubectl get node <node name> -o yaml` and look for the "Annotation" section...

    * Scale up forbidden window was protecting HPA against making decision to scale up based on metrics gathered during pod initialisation (which may be invalid, for example pod may be using a lot of CPU despite not doing any "actual" work).
    * To avoid that negative effect only use per pod metrics from pods that are:
    * - ready (so metrics about them should be valid), or

- Fixes an issue calculating total CPU usage reported for Windows nodes ([#122999](https://github.com/kubernetes/kubernetes/pull/122999), [@marosset](https://github.com/marosset)) [SIG Node and Windows]

- Fixed a bug where vSphere client connections where not being closed during testing. Leaked vSphere client sessions were causing resource exhaustion during automated testing. ([#107337](https://github.com/kubernetes/kubernetes/pull/107337), [@derek-pryor](https://github.com/derek-pryor))

- Kubeadm: fix a bug where file copy(backup) could not be executed correctly on Windows platform during upgrade ([#117861](https://github.com/kubernetes/kubernetes/pull/117861), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]