Has anyone been successful in enabling IPv6 for the Docker daemon?

[0xKubo]

To add IPv6 support to our Docker containers, one first needs to enable IPv6 support in the Docker daemon. More specifically for our Synology boxes, the daemon.json file is located at /var/packages/Docker/etc/dockerd.json. Which begs the question: do changes to this file persist across updates? If they don't, this could be an annoyance...

Anyway, setting "ipv6": true in the daemon.json file doesn't seem to work, the Docker service doesn't start with this option.

Has anyone been able to figure out why? How do we fix this?

 

[Rusty]

Can't help on that front I'm afraid. Still have no need for v6 so haven't tacked with this.

 

[0xKubo]

Well, I was using MACVLAN network for a specific container and that required to properly configure IPv6 for the whole thing. However, I've moved to host network for this container and now, as long as the host itself (the NAS) has an IPv6, it will also be associated to "network: host" containers.

 

[Rusty]

Well, I was using MACVLAN network for a specific container and that required to properly configure IPv6 for the whole thing. However, I've moved to host network for this container and now, as long as the host itself (the NAS) has an IPv6, it will also be associated to "network: host" containers.

So v6 is a problem for you I’m guessing? Have you tried to turn v6 off on your adapter on host level?

 

[0xKubo]

I think you misunderstood me... I had a problem with IPv6 when I was using a MACVLAN network for a specific container, to get that network with IPv6, Docker needs to support it to (which doesn't seem currently possible). I no longer have a problem because I switched the container to "host mode".

 

[Rusty]

Aha right. I did misread that. Still, I run all in bridge and on top of that no need for v6 on my end, so not sure what to tell you regarding troubleshoot.

 

[grashopper]

Hi, found this thread on a similar case as described by 0xKubo. Changing dockerd.json in /var/packages/Docker/etc/dockerd.json resulted in error while trying to restart docker service. I figured another dockerd.json existing in /volume1/@appstore/Docker/config/dockerd.json. After both files contained the same and new settings, docker service started as usually.

Here's what I've added to the files to activate ipv6 support:
"ipv6": true,
"fixed-cidr-v6": "2001:db8:1::/64"

The second line is necessary to receive a global ipv6. Otherwise the container would receive a local fe80: address only.
Received both config lines for ipv6 from here: Walkthrough: Enabling IPv6 Functionality for Docker & Docker Compose – Collabnix

Hope that helps