enable IPv6 cidr in microk8s

Hi
Recently we have started testing our apps in IPv6 env . We require our microk8s dev stations to support Dual Stack or IPv6 . I couldn't find any documentation or reference online .
Need some guidance whether adding IPv6 support to existing microk8s or scratch installing it .

Thanks,
Leon

[ktsakalozos]

Hi Leon. We haven't looked into IPv6 on MicroK8s yet. If you give me a set of steps/questions you need help with to enable IPv6 I might be able to guide you through. @johnsca knows more on what IPv6 needs.

Basically , how to add create the microk8s with IPv6 CIDR . if possible .

[jeanlucmongrain]

how to add create the microk8s with IPv6 CIDR

I'm looking to run microk8s with IPv6. And if possible with no IPv4

[BenjaminEHowe]

I'm looking to run microk8s with IPv6. And if possible with no IPv4

This is also my use-case; I'm not aware of a technical reason for needing to use IPv4 (for my use case!) and solely using IPv6 has certain advantages (public addresses everywhere with access controlled by firewalls, no risk of RFC1918 clashes, etc.).

I'm surprised that IPv6 isn't something that's been looked into - the first IPv6 RFC was published 25 years ago this month so it's not exactly a new technology!

[vifino]

I concur with the other people.
It's 2021, 90s tech should be implemented by now.

Kubernetes supports it, as does Calico. Now just microk8s needs to set the options.
https://docs.projectcalico.org/networking/ipv6

[mmulqueen]

I don't know whether this is useful to anyone, I didn't take this further because I ran into other problems:

You can enable dual stack editing the arguments in /var/snap/microk8s/current/args/ e.g. /var/snap/microk8s/current/args/kube-proxy:

--feature-gates="IPv6DualStack=true"
--service-cluster-ip-range=10.152.183.0/24,fd41:7f05:4867:9983::/108

Required arguments: https://kubernetes.io/docs/concepts/services-networking/dual-stack/

---

You can edit the settings for Calico in the kube-system namespace, there's daemonset/calico-node and configmaps/calico-config.

Details: https://docs.projectcalico.org/networking/ipv6#enable-dual-stack

I was able to get MicroK8S to start up and IPs were allocated when configuring a service with this included in the spec.

spec:
  ipFamilies:
  - IPv4
  - IPv6
  ipFamilyPolicy: RequireDualStack

I was unable to reach the service via IPv6 though. I didn't get to the bottom of this, but it could be the host's peculiar IPv6 settings (no default route for IPv6 and Calico says it requires a default route). Despite IPv6 not working, IPv4 continued to work fine.

[mmulqueen]

Not strictly related to this bug, but may be a suitable workaround for anyone that needs dual stack for external clients but not inside the cluster itself.

On daemonset/nginx-ingress-microk8s-controller in the ingress namespace, you can set .spec.template.spec.hostNetwork to true.

I'm unsure whether there are any other considerations, but may be worth exploring further.

Idea from https://github.com/leblancd/kube-v6/tree/master/dual-stack-ingress

[reingart]

Hi, I could configure microk8s with IPv6 dual stack and it works great!

Here are the detailed instructions: https://discuss.kubernetes.io/t/microk8s-ipv6-dualstack-how-to/14507

The steps are similar to @mmulqueen comments and other docs, with the following additions:

• enable net.ipv6.conf.all.forwarding via sysctl and apply firewall configs
• use IP6_AUTODETECTION_METHOD to avoid errors with some IPv6 networks
• install calicoctl to enable natOutgoing (egress traffic)
• deploy the service using IPv6 "only"

Working on Ubuntu desktop 16.04, 18.04 and Ubuntu server 20.04 (AWS EC2)

Could you confirm these are the correct steps?

BTW, it would be great if calicoctl could be added to the snap (it could event be used as a kubectl plugin)
I could help to enhance the docs and/or provide more testing about this topic.
If this has a chance to get included in microk8s, let me know and I can work in a PR.

Thanks for microk8s!

[ktsakalozos]

Very nice work @reingart, thank you!

@evilnick @chris-sanders should we promote this?

[krichter722]

@reingart I think your contributions on a microk8s feature/addon to enable IPv6 would be very welcome.

[mnj]

Any news on this? Missing IPv6 support makes this unusable for my use cases.

[xyzroller]

Any news on this? I've tried implementing the details linked to in #1343 (comment) in my Ansible playbooks, but just crashing against a wall every time. It would be good to have microk8s just start with dual-stack activated and no need to mess around in the configuration.