IPV6 property for Flannel addon

Hi, we recently experienced networking interfaces on our VM going up and down constantly. We found that the problem was IPV6 was turned on the VM but support for IPV6 is turned off by default in Flannel.

Considering the fact that IPV6 is present on many servers and our product is installed on servers we don’t control, we’d like to be able to turn on IPV6 for Flannel from the Kurl installer.


Hello Sabrina :wave: Today for our Flannel addon, IPV6 and dual stack networks aren’t supported. See - https://kurl.sh/docs/add-ons/flannel#limitations. Would you mind creating a feature request via Replicated for this re-iterating what you mentioned here as well as any other requirements you have?

Hi, i did a quick search about dual stack networks for kubernetes. It seems since 1.21 it’s turned on by default.

If it’s turned off in flannel, then the kurl installation should turn it off on kubernetes.

Yeah, the missing piece from Replicated’s standpoint that’s mentioned in the Prerequisites would be:

A network plugin that supports dual-stack networking.

This is where you’re currently seeing issues with Flannel.

Can’t the installer also disable ipv6 in kubernetes ?

Can’t the installer also disable ipv6 in kubernetes ?

Sorry for the late response here. I think at this point it would be best if you could get that feature request opened, so we can understand holistically the problem you faced, and what you’re trying to solve. It’s not clear from the support issue we worked with you on how much the ipv6 issues played into what you saw vs. the memory pressure on nginx.

We can evaluate further from the feature request any potential optimizations necessary in our ipv6 configuration in kURL when Flannel is used.

I’ve create this https://github.com/replicated-collab/redgate-kots/issues/94