chown docker volumes on host (possibly through docker-compose)

Question

I have the following example

version: '2'

services:
  proxy:
    container_name: proxy
    hostname: proxy
    image: nginx
    ports:
      - 80:80
      - 443:443
    volumes:
      - proxy_conf:/etc/nginx
      - proxy_htdocs:/usr/share/nginx/html

volumes:
  proxy_conf: {}
  proxy_htdocs: {}

which works fine. When I run docker-compose up it creates those named volumes in /var/lib/docker/volumes and all is good. However, from the host, I can only access /var/lib/docker as root, because it's root:root (makes sense). I was wondering if there is a way of chowning the host's directories to something more sensible/safe (like, my relatively unprivileged user that I use to do most things on the host) or if I just have to suck it up and chown them manually. I'm starting to have a number of scripts already to work around other issues, so having an extra couple of lines won't be much of a problem, but I'd really like to keep my self-written automation minimal, if I can -- fewer chances for stupid mistakes.

By the way, no: if I mount host directories instead of creating volumes, they get overlaid, meaning that if they start empty, they stay empty, and I don't get the default configuration (or whatever) from inside the container.

Extra points: can I just move the volumes to a more convenient location? Say, /home/myuser/myserverstuff/volumes?

Answer 1

It's best to not try to access files inside /var/lib/docker directly. Those directories are meant to be managed by the docker daemon, and not to be messed with.

To access the data inside a volume, there's a number of options;

• use a bind-mounted directory (you considered that, but didn't fit your use case).
• use a "service" container that uses the same volume and makes it accessible through that container, for example a container running ssh (to use scp) or a SAMBA container (such as svendowideit/samba)
• use a volume-driver plugin. there's various plugins around that offer all kind of options. For example, the local persist plugin is a really simple plug-in that allows you to specify where docker should store the volume data (so outside of /var/lib/docker)