### Deprecation

- 'kubeadm: marked the sub-phase of ''init kubelet-finilize'' called ''experimental-cert-rotation''
  as deprecated and print a warning if it is used directly; it will be removed in
  a future release. Add a replacement sub-phase ''enable-client-cert-rotation''.' ([#124419](https://github.com/kubernetes/kubernetes/pull/124419), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

- Always create configmaps/extensions-apiserver-authentication from kube-apiserver. ([#67694](https://github.com/kubernetes/kubernetes/pull/67694), [@sttts](https://github.com/sttts))
- Switched certificate data replacement from "REDACTED" to "DATA+OMITTED" ([#66023](https://github.com/kubernetes/kubernetes/pull/66023), [@ibrasho](https://github.com/ibrasho))

  // Note: This field is declared as mergeable, but the merge key is not sufficiently
  // unique, which can cause data corruption when it is merged. Callers should instead
  // use a full-replacement patch. See https://pr.k8s.io/79391 for an example.
  // Consumers should assume that addresses can change during the
  // lifetime of a Node. However, there are some exceptions where this may not

and the second value, of type <code>rune</code>, will be the value of
the corresponding code point. If the iteration encounters an invalid
UTF-8 sequence, the second value will be <code>0xFFFD</code>,
the Unicode replacement character, and the next iteration will advance
a single byte in the string.
</li>

<li>
The iteration order over maps is not specified
and is not guaranteed to be the same from one iteration to the next.

- The v1alpha1 PodPreset API and admission plugin has been removed with no built-in replacement. Admission webhooks can be used to modify pods on creation. ([#94090](https://github.com/kubernetes/kubernetes/pull/94090), [@deads2k](https://github.com/deads2k)) [SIG API Machinery, Apps, CLI, Cloud Provider, Scalability and Testing]

- The in-tree Azure plugin has been deprecated. The Azure kubelogin plugin serves as an out-of-tree replacement via the kubectl/client-go credential plugin mechanism.  Users will now see a warning in the logs regarding this deprecation. ([#107904](https://github.com/kubernetes/kubernetes/pull/107904), [@sabbey37](https://github.com/sabbey37))

FFF9..FFFB    ; disallowed                             # 3.0  INTERLINEAR ANNOTATION ANCHOR..INTERLINEAR ANNOTATION TERMINATOR
FFFC          ; disallowed                             # 2.1  OBJECT REPLACEMENT CHARACTER
FFFD          ; disallowed                             # 1.1  REPLACEMENT CHARACTER
FFFE..FFFF    ; disallowed                             # 1.1  <noncharacter-FFFE>..<noncharacter-FFFF>

IPVS is an alternative approach to in-cluster load balancing that uses in-kernel hash tables rather than the previous iptables approach, while CoreDNS is a replacement for kube-dns for service discovery.

### SIG Node

SIG-Node advanced several features and made incremental improvements in a few key topic areas this release.

### Network

In v1.9 SIG Network has implemented alpha support for IPv6, and alpha support for CoreDNS as a drop-in replacement for kube-dns. Additionally, SIG Network has begun the deprecation process for the extensions/v1beta1 NetworkPolicy API in favor of the networking.k8s.io/v1 equivalent.

### Node

PSP as an admission controller resource is being deprecated. Deployed PodSecurityPolicy's will keep working until version 1.25, their target removal from the codebase. A new feature, with a working title of "PSP replacement policy", is being developed in [KEP-2579](https://features.k8s.io/2579). To learn more, read [PodSecurityPolicy Deprecation: Past, Present, and Future](https://blog.k8s.io/2021/04/06/podsecuritypolicy-deprecation-past-present-and-future/).