### IPv4/IPv6 run

IPv4/IPv6 dual-stack has been reimplemented for 1.20 to support dual-stack Services, based on user and community feedback. If your cluster has dual-stack enabled, you can create Services which can use IPv4, IPv6, or both, and you can change this setting for existing Services. Details are available in updated [IPv4/IPv6 dual-stack docs](https://docs.k8s.io/concepts/services-networking/dual-stack/), which cover the nuanced array of options.

- `-- kube-controller-manager`
  `--node-cidr-mask-size-ipv4 int32`     Default: 24. Mask size for IPv4 node-cidr in dual-stack cluster.
`--node-cidr-mask-size-ipv6 int32`     Default: 64. Mask size for IPv6 node-cidr in dual-stack cluster.

    These 2 flags can be used only for dual-stack clusters. For non dual-stack clusters, continue to use  `--node-cidr-mask-size` flag to configure the mask size.

- Kube-proxy: Added dual-stack IPv4/IPv6 support to the iptables proxier. ([#82462](https://github.com/kubernetes/kubernetes/pull/82462), [@vllry](https://github.com/vllry)) [SIG Network]

### IPv4/IPv6 Dual-stack Networking graduates to GA

[IPv4/IPv6 dual-stack networking](https://github.com/kubernetes/enhancements/tree/master/keps/sig-network/563-dual-stack) graduates to GA.
Since 1.21, Kubernetes clusters are enabled to support dual-stack networking by default.
In 1.23, the `IPv6DualStack` feature gate is removed.
The use of dual-stack networking is not mandatory.

- [Topology Manager](https://github.com/kubernetes/enhancements/issues/693), a new Kubelet component, aims to co-ordinate resource assignment decisions to provide optimized resource allocations.
- [IPv4/IPv6 dual-stack](https://kubernetes.io/docs/concepts/services-networking/dual-stack) enables the allocation of both IPv4 and IPv6 addresses to Pods and Services.

- Users might specify the `kubectl.kubernetes.io/default-container` annotation in a Pod...

- Fixed a bug with dual stack clusters using the beta feature MultiCIDRServiceAllocator which could not create dual stack Services or Services with IPs in the secondary range. Users who wanted to use this feature in version 1.30 with dual stack clusters could work around the issue by setting the feature gate DisableAllocatorDualWrite to true. ([#127598](https://github.com/kube...

- kube-apiserver: Fixes an issue updating the default ServiceCIDR API object and creating dual-stack Service API objects when `--service-cluster-ip-range` flag passed to kube-apiserver is changed from single-stack to dual-stack. ([#131263](https://github.com/kubernetes/kubernetes/pull/131263), [@aojea](https://github.com/aojea)) [SIG API Machinery, Network and Testing]

- The `CloudDualStackNodeIPs` feature is now `beta`, meaning that when using
  an external cloud provider that has been updated to support the feature,
  you can pass comma-separated dual-stack `--node-ips` to `kubelet` and have
  the cloud provider take both IPs into account. ([#120275](https://github.com/kubernetes/kubernetes/pull/120275), [@danwinship](https://github.com/danwinship))

- Kubeadm: update `CoreDNS` to 1.8.4. Grant `CoreDNS` permissions to "list" and "watch" `EndpointSlice` objects to accommodate dual-stack support. ([#102466](https://github.com/kubernetes/kubernetes/pull/102466), [@pacoxu](https://github.com/pacoxu))