Add ability to update internal group ids

[Tzrlk]

I have a problem with my current use of fixuid, in that the docker socket I'm binding from the host has a different gid than the internal docker group. Consequently, adding the internal user to the "docker" group has no effect.

It'd be awesome if internal group gids could be remapped to account for this by either:

• Specifying an environment variable:

docker run -dt -u 123:123 -e FIXGID_DOCKER=984 ...

• Testing specific paths defined in the config:

...
groups:
  docker: /var/run/docker.sock

[polarathene]

Consequently, adding the internal user to the "docker" group has no effect.

? Shouldn't you be mapping the GID?(to the socket) I haven't used fixuid in this situation, but I'd assume it's not meant to have an ability to adjust the socket GID outside of the container, is there any reason that -u 123:984 would not work? On the host you could add your user to that group as it sounds rather host specific.

[Tzrlk]

This was a while ago, but I think I was asking to alter the internal docker user group id? Changing the socket id is indeed not a great idea.

[polarathene]

@Tzrlk I don't think that would work. If you're bind mounting something into the container, changing the UID/GID on either host or container side would affect the other wouldn't? Assign your user the GID within the container(they can have multiple groups), or pass it in via the --user flag(additional GID can be given with --group-add).

[caleblloyd]

Yes, I believe @polarathene solution is the best here - use --group-add and add the host docker GID