How to assign IPv6 address with docker-compose

Question

I am using docker 1.12.1 on Ubuntu 16.04, and docker-compose 1.8.1. I am trying to get the Compose file from https://docs.docker.com/compose/compose-file/#ipv4-address-ipv6-

Answer 1

It turns out this is indeed a docker-compose bug that is going to be fixed in 1.9.0.

Meanwhile, there is a workaround by creating a custom network with the docker network command:

docker network create --subnet=172.16.2.0/24 --gateway=172.16.2.1 --ipv6 --subnet= dockerbridge

... which can then be made available inside docker-composed.yml by writing

networks:
  dockerbridge:
    external:
      name: dockerbridge