* - Add PodSecurityPolicies for cluster addons ([#55509](https://github.com/kubernetes/kubernetes/pull/55509), [@tallclair](https://github.com/tallclair))
    * - Remove SSL cert HostPath volumes from heapster addons

performing a GET then PUT, the kube-apiserver must write the canonical representation of the object to etcd if the current value does not match. That allows external agents to migrate content in etcd from one API version to another, across different storage types, or across varying encryption levels. This fixes a bug introduced in 1.5 where we unintentionally stopped writing the newest data. ([#48394](https://github.com/kubernetes/kubernetes/pull/48394), [@smarterclayton](https://github.com/smarterclayton))...

*   PodSecurityPolicies have been added for all in-tree cluster addons ([#55509](https://github.com/kubernetes/kubernetes/pull/55509),[ @tallclair](https://github.com/tallclair))

#### **GCE**

- For volumes that allow attaches across multiple nodes, attach and detach operations across different nodes are now executed in parallel. ([#88678](https://github.com/kubernetes/kubernetes/pull/88678), [@verult](https://github.com/verult)) [SIG Storage]

- For volumes that allow attaches across multiple nodes, attach and detach operations across different nodes are now executed in parallel. ([#89239](https://github.com/kubernetes/kubernetes/pull/89239), [@verult](https://github.com/verult)) [SIG Apps, Node and Storage]

  If the `DeclarativeValidationTakeover` feature gate was enabled, declarative validation was the primary source of errors for migrated fields. ([#133013](https://github.com/kubernetes/kubernetes/pull/133013), [@aaron-prindle](https://github.com/aaron-prindle)) [SIG API Machinery and Auth]

    - [libvirt CoreOS](#libvirt-coreos)
    - [GCE](#gce-1)
    - [OpenStack](#openstack)
    - [Container Images](#container-images)
    - [Other Notable Changes](#other-notable-changes-16)
  - [Changes to Addons](#changes-to-addons)
    - [Dashboard](#dashboard)
    - [DNS](#dns)
    - [DNS Autoscaler](#dns-autoscaler)
    - [Cluster Autoscaler](#cluster-autoscaler-1)
    - [Cluster Load Balancing](#cluster-load-balancing)

  
  Multi vCenter support is deprecated as of v1.21. If you have a Kubernetes cluster spanning across multiple vCenter servers, please consider moving all k8s nodes to a single vCenter Server. vSphere CSI Driver does not support Kubernetes deployment spanning across multiple vCenter servers.
  

## Changes by Kind

### API Change

- Fixes a 1.33 regression that can cause a nil panic in kube-scheduler when aggregating resource requests across container's spec and status. ([#133285](https://github.com/kubernetes/kubernetes/pull/133285), [@yue9944882](https://github.com/yue9944882)) [SIG Node and Scheduling]

### Feature

  - support for the `v1alpha3` configuration file format is deprecated and will be removed in 1.14. Use `kubeadm config migrate` to migrate `v1alpha3` configuration files to `v1beta1`, which provides improvements in image repository management, addons configuration, and other areas. The documentation for `v1beta1` can be found here: https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1