- A namespaced object with an ownerReference referencing a uid of a namespaced kind which does not exist in the same namespace is now consistently treated as though that owner does not exist, and the child object is deleted.

* Add CSI Migration Shim for VerifyVolumesAreAttached and BulkVolumeVerify ([#80443](https://github.com/kubernetes/kubernetes/pull/80443), [@davidz627](https://github.com/davidz627))

a safe location. `kubadm certs renew` will renew the certificate in `super-admin.conf` to one year if the file exists; if it does not exist a "MISSING" note will be printed. `kubeadm upgrade apply` for this release will migrate this particular node to the two file setup. Subsequent kubeadm releases will continue to optionally renew the certificate in `super-admin.conf` if the file exists on disk and if renew on upgrade is not disabled. `kubeadm join --control-plane` will now generate only an `admin.conf`...

* Fixes issue for readOnly subpath mounts for SELinux systems and when the volume mountPath already existed in the container image. ([#64351](https://github.com/kubernetes/kubernetes/pull/64351), [@msau42](https://github.com/msau42))

* Fixes issue for readOnly subpath mounts for SELinux systems and when the volume mountPath already existed in the container image. ([#64351](https://github.com/kubernetes/kubernetes/pull/64351), [@msau42](https://github.com/msau42))

* Fix security holes in GCE metadata proxy. ([#51302](https://github.com/kubernetes/kubernetes/pull/51302), [@ihmccreery](https://github.com/ihmccreery))
* Fixed an issue looking up cronjobs when they existed in more than one API version ([#52227](https://github.com/kubernetes/kubernetes/pull/52227), [@liggitt](https://github.com/liggitt))

- Kubeadm: during "join", don't re-add an etcd member if it already exists in the cluster. ([#92118](https://github.com/kubernetes/kubernetes/pull/92118), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]
- hyperkube: Use debian-hyperkube-base@v1.1.1 image
  

The following PRs changed the API spec:

- Kube-apiserver: Fixed a possible panic validating a custom resource whose `CustomResourceDefinition` indicates a status subresource exists, but which does not define a `status` property in the `openAPIV3Schema`. ([#133721](https://github.com/kubernetes/kubernetes/pull/133721), [@fusida](https://github.com/fusida)) [SIG API Machinery, Apps, Architecture, Auth, Autoscaling, CLI, Cloud...

moving the Kubelet plugin registration mechanism to beta, adding alpha support for a new CSI driver registry as well as for topology, and adding a number of alpha features to support the use of CSI for “local ephemeral volumes” (that is, volumes that exist for the lifecycle of a pod and contain some injected information, like a token or secret).

With Kubernetes v1.12, SIG Storage also introduced alpha support for [volume snapshotting](https://github.com/kubernetes/enhancements/issues/177)....