How to enable IPv6 in docker compose version: >= 3?

Question

I need to enable both IPv4/IPv6 dualstack support for my docker containers. My docker compose file is version 3. By default IPv4 is enabled but how do I enable IPv6 for my docker containers/network?

I have already tried to update the docker daemon by updating the daemon.json and I know the updates are being recognised because Docker will not start if there are errors in the file. I have restarted Docker (not just my containers) after making the changes, but still no IPv6 addresses for my containers.

I have discovered that enable_ipv6: true in the docker compose file is not valid for version 3 or greater and I would not like to downgrade by file version.

My updated daemon.json:

{
  "ipv6": true,
  "fixed-cidr-v6": "2001:db8:1::/64"
}

When I inspect my containers, after making changes to the daemon.json, with docker inspect {id} I see the following:

"NetworkSettings": {
            "Bridge": "",
            "SandboxID": "df737362d15722fc1b0501ac256ba371417fe513dede807f2a17bd0524630a31",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "9000/tcp": null
            },
            "SandboxKey": "/var/run/docker/netns/df737362d157",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "",
            "Gateway": "",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "",
            "IPPrefixLen": 0,
            "IPv6Gateway": "",
            "MacAddress": "",
            "Networks": {
                "healixportal_default": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": [
                        "php-fpm",
                        "9b8a7aee156b"
                    ],
                    "NetworkID": "5523ae0a4a936b47f212f0e301b64cbbad1f279a33107ed1f624e28d2df96c66",
                    "EndpointID": "880e13b64bec3fc84ae5a0abb5054bda66d5f439da6853f3538eb33be14b256b",
                    "Gateway": "172.18.0.1",
                    "IPAddress": "172.18.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:12:00:02",
                    "DriverOpts": null
                }
            }
        }

So there is still no IPv6 address assigned to my container...

Answer 1

According to this issue for the compose repo IPv6 is not supported like that yet, but there is a workaround that might do the trick for you:

You must comment enable_ipv6: true, and leave all the others parameters as the documentation says. After running:

$ sudo docker-compose build

Then execute:

$ docker network create --driver bridge --ipv6 --subnet fd15:555::/64 --subnet 172.16.238.0/24 containerName-dockerfile_app_net --attachable

$ sudo docker-compose up -d