Docker --volumes-from权限

Question

I'm very new to Docker so I might be missing something, my data volume folder has root as owner.

Here is what I do (using the nginx reverse proxy):

# Data volume container
docker create -v <data path> --name <app>-data tianon/true
# Webapp container
docker run --volumes-from <app>-data --name <app> \
  -e VIRTUAL_HOST=<url> \
  <image> &

But nginx can't write into the data folder, and if I go in my container:

drwxr-xr-x  2 root     root       4096 Dec 16 19:03 data
drwxr-xr-x  3 www-data www-data   4096 Dec 16 18:57 doc
drwxr-xr-x  2 www-data www-data   4096 Dec 16 18:57 images

I do a chown in my Dockerfile image, but it looks like --volumes-from changes that.

What should I do to give the data folder www-data ownership?

Answer 1

In theory ( issue 2259 ):

If you chown the volume (on the host side) before bind-mounting it, it will work.

In that case, you could do:

mkdir /tmp/www
chown 101:101 /tmp/www
docker run -v /tmp/www:/var/www ubuntu stat -c "%U %G" /var/www

(Assuming that 101:101 is the UID:GID of the www-data user in your container.)

Note that it is not what you are doing: you are mounting an host folder in a data volume container (a tianon/true image, which is quite empty, see its Dockerfile ), and then mounting that data volume container into a regular container.

Still, that might work.