<p>I installed a kubernetes v1.16 cluster with two nodes, and enabled "IPv4/IPv6 dual-stack", following <a href="https://kubernetes.io/docs/concepts/services-networking/dual-stack/" rel="nofollow noreferrer">this guide</a>. For "dual-stack", I set <code>--network-plugin=kubenet</code> to kubelet.</p>

<p>Now, the pods have ipv4 and ipv6 address, and each node has a cbr0 gw with both ipv4 and ipv6 address.
But when I ping from a node to the cbr0 gw of other node, it failed.</p>

<p>I tried to add route as follow manually: 
"ip route add [podCIDR of other node] via [ipaddress of other node]"</p>

<p>After I added the route on two nodes, I can ping cbr0 gw successful with ipv4.
But "adding route manually" does not seem to be a correct way.</p>

<p>When I use kubenet, how should I config to ping from a node to the cbr0 gw of other node?</p>

<p>Kubenet is a <a href="https://kubernetes.io/docs/concepts/services-networking/dual-stack/#prerequisites" rel="nofollow noreferrer">requirement</a> for enabling IPv6 and as you stated, kubenet have some limitations and <a href="https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/#kubenet" rel="nofollow noreferrer">here</a> we can read:</p>

<blockquote>
  <p><strong>Kubenet is a very basic, simple network plugin</strong>, on Linux only. <strong>It does
  not, of itself, implement more advanced features</strong> like cross-node
  networking or network policy. It is typically used together with a
  <strong>cloud provider that sets up routing rules</strong> for communication between
  nodes, or in single-node environments.</p>
</blockquote>

<p>I would like to highlight that kubenet is not creating routes automatically for you. </p>

<p>Based on this information we can understand that in your scenario <strong>this is the expected behavior and there is no problem happening.</strong> 
If you want to keep going in this direction you need to create routes manually. </p>

<p>It's important to remember this is an alpha feature (WIP).</p>

<p>There is also some work being done to make it possible to bootstrap a <a href="https://github.com/kubernetes/kubeadm/issues/1612" rel="nofollow noreferrer">Kubernetes cluster with Dual Stack using Kubeadm</a>, but it's not usable yet and there is no ETA for it. </p>

<p>There are some examples of IPv6 and dual-stack setups with other networking plugins in <a href="https://github.com/Nordix/k8s-ipv6/tree/dual-stack" rel="nofollow noreferrer">this repository</a>, but it still require adding routes manually.</p>

<blockquote>
  <p>This project serves two primary purposes: (i) study and validate ipv6
  support in kubernetes and associated plugins (ii) provide a dev
  environment for implementing and testing additional functionality
  <strong>(e.g.dual-stack)</strong></p>
</blockquote>
