* kube-apiserver: The external hostname no longer longer use the cloud provider API to select a default. It can be set explicitly using --external-hostname, if needed. If there is no default, AdvertiseAddress or os.Hostname() will be used, in that order. ([#56812](https://github.com/kubernetes/kubernetes/pull/56812), [@dims](https://github.com/dims))

*   The kubeadm `--skip-preflight-checks` flag is now deprecated and will be removed in a future release.
*   If you are using the cloud provider API to determine the external host address of the apiserver, set `--external-hostname` explicitly instead. The cloud provider detection has been deprecated and will be removed in the future ([#54516](https://github.com/kubernetes/kubernetes/pull/54516),[ @dims](https://github.com/dims))

### **Multicluster**

- `StatefulSet` names must be DNS labels, rather than subdomains. Any `StatefulSet`
  which took advantage of subdomain validation (by having dots in the name) can't
  possibly have worked, because we eventually set `pod.spec.hostname` from the `StatefulSetName`,
  and that is validated as a DNS label. ([#114172](https://github.com/kubernetes/kubernetes/pull/114172), [@thockin](https://github.com/thockin))

### SIG Network

- Corrected family type (inet6) for ipsets in ipv6-only clusters ([#68436](https://github.com/kubernetes/kubernetes/pull/68436), [@uablrek](https://github.com/uablrek))
- kube-proxy argument `hostname-override` can be used to override hostname defined in the configuration file ([#69340](https://github.com/kubernetes/kubernetes/pull/69340), [@stevesloka](https://github.com/stevesloka))

* kube-proxy needs to be configured to override hostname in some environments. ([#857](https://github.com/kubernetes/kubeadm/issues/857), [@detiber](https://github.com/detiber))

### SIG Cloud Provider

- The cloudstack cloud provider now reports a `Hostname` address type for nodes based on the `local-hostname` metadata key. ([#67719](https://github.com/kubernetes/kubernetes/pull/67719), [@liggitt](https://github.com/liggitt))

- Fix panic in kubelet when running IPv4/IPv6 dual-stack mode with a CNI plugin ([#82508](https://github.com/kubernetes/kubernetes/pull/82508), [@aanm](https://github.com/aanm))
- EndpointSlice hostname is now set in the same conditions Endpoints hostname is. ([#84207](https://github.com/kubernetes/kubernetes/pull/84207), [@robscott](https://github.com/robscott))

- Fix isCurrentInstance for Windows by removing the dependency of hostname. ([#89138](https://github.com/kubernetes/kubernetes/pull/89138), [@feiskyer](https://github.com/feiskyer)) [SIG Cloud Provider]

## Changelog since v1.8.1

### 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))

    * as being in state "Unknown", along with a longer description in `kubectl describe` output.