1. When configuring a dual-stack cluster, the user must specify both `--node-cidr-mask-size-ipv4` and `--node-cidr-mask-size-ipv6` to set the per-node IP mask sizes, instead of the previous `--node-cidr-mask-size` flag.
  2. The `--node-cidr-mask-size` flag is mutually exclusive with `--node-cidr-mask-size-ipv4` and `--node-cidr-mask-size-ipv6`.

- Add possibility to configure controller manager to use IPv6 dual stack:
  use `--cluster-cidr="<cidr1>,<cidr2>"`.
  Notes:
  1. Only the first two CIDRs are used (soft limits for Alpha, might be lifted later on).
  2. Only the "RangeAllocator" (default) is allowed as a value for `--cidr-allocator-type`. Cloud allocators are not compatible with IPv6 dual stack

**Action required** for Kubernetes cluster administrators and for distributions that manage the cluster Service CIDR.
Kubernetes now allows users to define the cluster Service CIDR via an API object: ServiceCIDR.

* Avoid unnecessary spam in kube-controller-manager log if --cluster-cidr is not specified and --allocate-node-cidrs is false. ([#54934](https://github.com/kubernetes/kubernetes/pull/54934), [@akosiaris](https://github.com/akosiaris))

* Fix overlay2 container disk metrics for Docker and CRI-O ([#54827](https://github.com/kubernetes/kubernetes/pull/54827), [@dashpole](https://github.com/dashpole))
* API machinery's httpstream/spdy calls now support CIDR notation for NO_PROXY ([#54413](https://github.com/kubernetes/kubernetes/pull/54413), [@kad](https://github.com/kad))

- Kube-controller-manager: volume plugins can be restricted from contacting local and loopback addresses by setting `--volume-host-allow-local-loopback=false`, or from contacting specific CIDR ranges by setting `--volume-host-cidr-denylist` (for example, `--volume-host-cidr-denylist=127.0.0.1/28,feed::/16`) ([#91785](https://github.com/kubernetes/kubernetes/pull/91785), [@mattcary](https://github.com/mattcary)) [SIG API Machinery, Apps, Auth, CLI, Network, Node, Storage and Testing]...

- KEP-1880: Users of the new feature to add multiple service CIDR will use by default a dual-write strategy on the new ClusterIP allocators to avoid the problem of possible duplicate IPs allocated to Services when running skewed kube-apiservers using different allocators. They can opt-out of this behavior by enabled...

  * Add ip-masq-agent addon to the addons folder which is used in GCE if `--non-masquerade-cidr` is set to 0/0 ([#46038](https://github.com/kubernetes/kubernetes/pull/46038), [@dnardo](https://github.com/dnardo))

- Kubeadm: skip validating pod subnet against node-cidr-mask when allocate-node-cidrs is set to be false ([#98984](https://github.com/kubernetes/kubernetes/pull/98984), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

  and removed `--short` flag entirely. ([#116720](https://github.com/kubernetes/kubernetes/pull/116720), [@soltysh](https://github.com/soltysh))
- Kube-controller-manager deprecate `--volume-host-cidr-denylist` and `--volume-host-allow-local-loopback` flags. ([#118128](https://github.com/kubernetes/kubernetes/pull/118128), [@carlory](https://github.com/carlory)) [SIG API Machinery, Apps, Network, Node, Storage and Testing]