* Restored the pre-1.10 behavior of the openstack cloud provider, which uses the instance name as the Kubernetes Node name. This requires instances be named with RFC-1123 compatible names. ([#63903](https://github.com/kubernetes/kubernetes/pull/63903), [@liggitt](https://github.com/liggitt))

* Modified influxdb petset to provision persistent  volume. ([#28840](https://github.com/kubernetes/kubernetes/pull/28840), [@jszczepkowski](https://github.com/jszczepkowski))
* Allow service names up to 63 characters (RFC 1035) ([#29523](https://github.com/kubernetes/kubernetes/pull/29523), [@fraenkel](https://github.com/fraenkel))

- Allowed setting the `hostnameOverride` field in `PodSpec` to specify any RFC 1123 DNS subdomain as the pod's hostname. The `HostnameOverride` feature gate was introduced to control enablement of this functionality. ([#132558](https://github.com/kubernetes/kubernetes/pull/132558), [@HirazawaUi](https://github.com/HirazawaUi))...

- Added warnings to the Services API. Kubernetes now warns for Services in the case of:
  - IPv4 addresses with leading zeros
  - IPv6 address in non-canonical format (RFC 5952) ([#114505](https://github.com/kubernetes/kubernetes/pull/114505), [@aojea](https://github.com/aojea))

- The feature gate `RootCAConfigMap` graduated to GA in v1.21 and therefore will be unconditionally enabled. This flag will...

- Kubeadm: external etcd endpoints passed in the `ClusterConfiguration` that have Unicode characters are no longer IDNA encoded (converted to Punycode). They are now just URL encoded as per Go's implementation of RFC-3986, have duplicate "/" removed from the URL paths, and passed like that directly to the `kube-apiserver` `--etcd-servers` flag. If you have etcd endpoints that have Unicode characters, it is advisable to encode them in advance with tooling that is...

- Modify DNS-1123 error messages to indicate that RFC 1123 is not followed exactly ([#94182](https://github.com/kubernetes/kubernetes/pull/94182), [@mattfenwick](https://github.com/mattfenwick)) [SIG API Machinery, Apps, Auth, Network and Node]

* Restores the pre-1.10 behavior of the openstack cloud provider which uses the instance name as the Kubernetes Node name. This requires instances be named with RFC-1123 compatible names. ([#63903](https://github.com/kubernetes/kubernetes/pull/63903), [@liggitt](https://github.com/liggitt))

* Fix log spam due to unnecessary status update when node is deleted. ([#45923](https://github.com/kubernetes/kubernetes/pull/45923), [@verult](https://github.com/verult))
* GCE installs will now avoid IP masquerade for all RFC-1918 IP blocks, rather than just 10.0.0.0/8.  This means that clusters can ([#46473](https://github.com/kubernetes/kubernetes/pull/46473), [@thockin](https://github.com/thockin))