- `-- 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.

	* ip-masq-agent is now on by default for GCE ([#47794](https://github.com/kubernetes/kubernetes/pull/47794), [@dnardo](https://github.com/dnardo))

  PodSubnet validates against the corresponding cluster "--node-cidr-mask-size" of the kube-controller-manager, it fail if the values are not compatible.
  kubeadm no longer sets the node-mask automatically on IPv6 deployments, you must check that your IPv6 service subnet mask is compatible with the default node mask /64 or set it accordingly.

  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`.

- Node labels `beta.kubernetes.io/metadata-proxy-ready`, `beta.kubernetes.io/metadata-proxy-ready` and `beta.kubernetes.io/kube-proxy-ds-ready` are no longer added on new nodes.
  - ip-mask-agent addon starts to use the label `node.kubernetes.io/masq-agent-ds-ready` instead of `beta.kubernetes.io/masq-agent-ds-ready` as its node selector.

</p>

<pre>
make(map[string]int)
make(map[string]int, 100)
</pre>

<p>
The initial capacity does not bound its size:
maps grow to accommodate the number of items
stored in them, with the exception of <code>nil</code> maps.
A <code>nil</code> map is equivalent to an empty map except that no elements
may be added.
</p>

<h3 id="Channel_types">Channel types</h3>

<p>

* Bump ip-masq-agent to v2.1.1 ([#67916](https://github.com/kubernetes/kubernetes/pull/67916), [@MrHohn](https://github.com/MrHohn))
    * Update debian-iptables image for CVEs.
    * Change chain name to IP-MASQ to be compatible with the pre-injected masquerade rules.

- The scheduling queue didn't notice any extenders' failures, it could miss some cluster events,
  and it could end up Pods rejected by Extenders stuck in unschedulable pod pool in 5min in the worst-case scenario.

- Fixed a bug that caused the `apiserver` to panic when trying to allocate a Service with a dynamic `ClusterIP` and was configured with Service CIDRs with a /28 mask for IPv4 and a /124 mask for IPv6 ([#115322](https://github.com/kubernetes/kubernetes/pull/115322), [@aojea](https://github.com/aojea))
- Fixed a bug where Kubernetes would apply a default StorageClass to a PersistentVolumeClaim,

- GCE clusters will include some IP ranges that are not used on the public Internet in the list of non-masq IPs. Bumped ip-masq-agent version to v2.3.0 with flag `nomasq-all-reserved-ranges` turned on. ([#77458](https://github.com/kubernetes/kubernetes/pull/77458), [@grayluck](https://github.com/grayluck))