- The `apiserver` exposes 4 new metrics that allow to track the status of the Service CIDRs allocations:
      - current number of available IPs per Service CIDR
      - current number of used IPs per Service CIDR
      - total number of allocation per Service CIDR
      - total number of allocation errors per ServiceCIDR ([#104119](https://github.com/kubernetes/kubernetes/pull/104119), [@aojea](https://github.com/aojea))

  // the ReadOnly setting in VolumeMounts.
  // +optional
  optional bool readOnly = 5;

  // kind expected values are Shared: multiple blob disks per storage account  Dedicated: single blob disk per storage account  Managed: azure managed data disk (only in managed availability set). defaults to shared
  optional string kind = 6;
}

* Reduce Metrics Server memory requirement from 140Mi + 4Mi per node to 40Mi + 4Mi per node. ([#58391](https://github.com/kubernetes/kubernetes/pull/58391), [@kawych](https://github.com/kawych))

* kubeadm - Ensure the peer port is secured by explicitly setting the peer URLs for the default etcd instance. ([#64988](https://github.com/kubernetes/kubernetes/pull/64988), [@detiber](https://github.com/detiber))
    * kubeadm - Ensure that the etcd certificates are generated using a proper CN
    * kubeadm - Update generated etcd peer certificate to include localhost addresses for the default configuration.

*   `conversion-gen` is now usable in a context without a vendored k8s.io/kubernetes. The Kubernetes core API is removed from `default extra-peer-dirs`. ([#54394](https://github.com/kubernetes/kubernetes/pull/54394),[ @sttts](https://github.com/sttts))

	type parameter with a <a href="#Core_types">core type</a>,
	and that core type unifies with the other type per the
	unification rules for <code>≡<sub>A</sub></code>
	(loose unification at the top level and exact unification
	for element types).
</li>
</ul>

<p>
If both types are bound type parameters, they unify per the given
matching modes if:
</p>

<ul>
<li>
	Both type parameters are identical.

### Cloud Provider
- Azure: update disk lock logic per vm during attach/detach to allow concurrent updates for different nodes. ([#85115](https://github.com/kubernetes/kubernetes/pull/85115), [@aramase](https://github.com/aramase))

## Changelog since v1.8.12

### Other notable changes

* Add MAX_PODS_PER_NODE env so that user can use it to specify the default max pods per node for the cluster. IP_ALIAS_SIZE will be changed accordingly. Must have ip alias enabled. ([#63466](https://github.com/kubernetes/kubernetes/pull/63466), [@grayluck](https://github.com/grayluck))

  - Clients should reload the token from disk periodically (once per minute is recommended) to ensure they continue to use a valid token. `k8s.io/client-go` version v11.0.0+ and v0.15.0+ reload tokens automatically.

- Support for proxying a request to a peer kube-apiserver if the local apiserver is not able to serve it due to version skew or in the case the requested api is disabled on the local apiserver ([#117740](https://github.com/kubernetes/kubernetes/pull/117740), [@Richabanker](https://github.com/Richabanker))...