* client-go: alpha support for out-of-tree exec-based credential providers. For example, a cloud provider could create their own authentication system rather than using the standard authentication provided with Kubernetes. ([#59495](https://github.com/kubernetes/kubernetes/pull/59495), [@ericchiang](https://github.com/ericchiang))

*   Add-on manager now supports HA masters. ([#55466](https://github.com/kubernetes/kubernetes/pull/55466),[ #55782](https://github.com/x13n),[ @x13n](https://github.com/x13n))
*   Hyperkube can now run from a non-standard path. ([#54570](https://github.com/kubernetes/kubernetes/pull/54570))

#### **GCP**

- Remove `kubernetes.io/grpc` standard appProtocol ([#116866](https://github.com/kubernetes/kubernetes/pull/116866), [@LiorLieberman](https://github.com/LiorLieberman)) [SIG API Machinery and Apps]

- Fix: azure data disk should use same key as os disk by default ([#86351](https://github.com/kubernetes/kubernetes/pull/86351), [@andyzhangx](https://github.com/andyzhangx)) [SIG Cloud Provider]
- Fix: azure disk could not mounted on Standard_DC4s/DC2s instances ([#86612](https://github.com/kubernetes/kubernetes/pull/86612), [@andyzhangx](https://github.com/andyzhangx)) [SIG Cloud Provider and Storage]

* Allow disable outbound SNAT when Azure standard load balancer is used together with outbound rules.  ([#75282](https://github.com/kubernetes/kubernetes/pull/75282), [@feiskyer](https://github.com/feiskyer))

### Other notable changes

* Allow for configuring etcd hostname in the manifest ([#54403](https://github.com/kubernetes/kubernetes/pull/54403), [@wojtek-t](https://github.com/wojtek-t))
* Allow standard flags in client-gen. ([#53999](https://github.com/kubernetes/kubernetes/pull/53999), [@sttts](https://github.com/sttts))

- External credential provider plugins will now have their standard error output logged by kubelet upon failures. ([#117448](https://github.com/kubernetes/kubernetes/pull/117448), [@cartermckinnon](https://github.com/cartermckinnon))

  -  Remove already deprecated options `resyncperiod` and `upstream` in the Kubernetes plugin.
  -  Includes Prometheus metrics name changes (to bring them in line with standard Prometheus metrics naming convention). They will be backward incompatible with existing reporting formulas that use the old metrics' names.
  -  The federation plugin (allows for v1 Kubernetes federation) has been removed.

### CSI Volume Snapshot graduates to General Availability

CSI Volume Snapshot moves to GA in the 1.20 release. This feature provides a standard way to trigger volume snapshot operations in Kubernetes and allows Kubernetes users to incorporate snapshot operations in a portable manner on any Kubernetes environment regardless of supporting underlying storage providers.

  CVE-2021-29923 golang standard library "net" - Improper Input Validation of octal literals in golang 1.16.2 and below standard library "net" results in indeterminate SSRF & RFI vulnerabilities.