- Added support for max attach limit for Cinder ([#72980](https://github.com/kubernetes/kubernetes/pull/72980), [@gnufied](https://github.com/gnufied))
- Enabled mTLS encryption between etcd and kube-apiserver in GCE ([#70144](https://github.com/kubernetes/kubernetes/pull/70144), [@wenjiaswe](https://github.com/wenjiaswe))

- Communication between the etcd server and kube-apiserver on master is now overridden to use HTTPS instead of HTTP when mTLS is enabled in GCE. ([#74690](https://github.com/kubernetes/kubernetes/pull/74690), [@wenjiaswe](https://github.com/wenjiaswe))

### GCP

- [stackdriver addon] Bumped prometheus-to-sd to v0.5.0 to pick up security fixes.

	// Configures the revision this control plane is a part of
	Revision string `protobuf:"bytes,59,opt,name=revision,proto3" json:"revision,omitempty"`
	// Controls whether the in-cluster MTLS key and certs are loaded from the secret volume mounts.
	MountMtlsCerts *wrapperspb.BoolValue `protobuf:"bytes,60,opt,name=mountMtlsCerts,proto3" json:"mountMtlsCerts,omitempty"`
	// The address of the CA for CSR.

for google sink. ([#57902](https://github.com/kubernetes/kubernetes/pull/57902), [@kawych](https://github.com/kawych))

* On cluster provision or upgrade, kubeadm now generates certs and secures all connections to the etcd static-pod with mTLS. This includes the etcd serving cert, the etcd peer cert, and the apiserver etcd client cert. Flags and hostMounts are added to the etcd and apiserver static-pods to load these certs. For connections to etcd, https is now used in favor of http. ([...

    * If you are using docker manifests there are not visible changes.

### Other notable changes

* Use HTTPS as etcd-apiserver protocol when mTLS between etcd and kube-apiserver on master is enabled, change etcd metrics/health port to 2382. ([#77561](https://github.com/kubernetes/kubernetes/pull/77561), [@wenjiaswe](https://github.com/wenjiaswe))