- kube-controller-manager now uses the informer cache instead of active pod gets in HPA controller ([#68241](https://github.com/kubernetes/kubernetes/pull/68241), [@krzysztof-jastrzebski](https://github.com/krzysztof-jastrzebski))

    * In 1.16, the masq-agent daemonset add-on will switch to using `node.kubernetes.io/masq-agent-ds-ready` as a node selector.
* Kubelet: replace `du` and `find` with a golang implementation ([#74675](https://github.com/kubernetes/kubernetes/pull/74675), [@dashpole](https://github.com/dashpole))
    * Kubelet: periodically update machine info to support hot-add/remove

## Before Upgrading

* If you need to downgrade from 1.10 to 1.9.x, downgrade to v1.9.6 to ensure PV and PVC objects can be deleted properly.

* In-place node upgrades to this release from versions 1.7.14, 1.8.9, and 1.9.4 are not supported if using subpath volumes with PVCs.  Such pods should be drained from the node first.

* 'kubefed init' now supports overriding the default etcd image name with the --etcd-image parameter. ([#46247](https://github.com/kubernetes/kubernetes/pull/46247), [@marun](https://github.com/marun))
* remove the elasticsearch template ([#45952](https://github.com/kubernetes/kubernetes/pull/45952), [@harryge00](https://github.com/harryge00))

* Remove DirectCodecFactory(replace with serializer.WithoutConversionCodecFactory), DirectEncoder(replace with runtime.WithVersionEncoder) and DirectDecoder(replace with runtime.WithoutVersionDecoder). action required ([#79263](https://github.com/kubernetes/kubernetes/pull/79263), [@draveness](https://github.com/draveness))

release is the work on moving internal APIs that the vSphere provider depends upon to staging to guarantee API stability. This work is being done in conjunction with SIG Cloud Provider and includes the creation of a brand new vsphere-csi plugin to replace the current volume functionalities in-tree.

Additional work was also done to implement a vSphere provider for the Cluster API effort lead by SIG Cluster Lifecycle. For the out-of-tree vSphere cloud provider, the SIG largely focused on...

## Changes by Kind

### API Change

- Revert regression that prevented client-go latency metrics to be reported with a template URL to avoid label cardinality. ([#112055](https://github.com/kubernetes/kubernetes/pull/112055), [@aanm](https://github.com/aanm)) [SIG API Machinery]

### Feature

* [IPVS] Allow for transparent kube-proxy restarts ([#75283](https://github.com/kubernetes/kubernetes/pull/75283), [@lbernail](https://github.com/lbernail))

the respective mapping <code>P ➞ A</code> from type parameter to argument
is added to the map.
Conversely, when comparing types, a known type argument
(a type argument for which a map entry already exists)
takes the place of its corresponding type parameter.
As type inference progresses, the map is populated more and more
until all equations have been considered, or until unification fails.

  apiserver_flowcontrol_current_executing_requests ([#119110](https://github.com/kubernetes/kubernetes/pull/119110), [@andrewsykim](https://github.com/andrewsykim)) [SIG API Machinery and Instrumentation]
- Replace `apiserver_storage_db_total_size_in_bytes` with `apiserver_storage_size_bytes` metric ([#118812](https://github.com/kubernetes/kubernetes/pull/118812), [@serathius](https://github.com/serathius)) [SIG API Machinery, Instrumentation and Testing]