Using volumes does not work as explained in docs. This breaks projects like fig.

[bercab]

In newer versions of docker (>= v1.4.0), docker-py does not bind-mount volumes.

If volume is specified in volumes parameter to c.create_container(), then volume is created. But according to docs, when binds parameter is specified to c.start(), volume should be bind mounted.

http://docker-py.readthedocs.org/en/latest/volumes/

But it seems that start() only binds volumes NOT specified on volumes parameter of c.create_volumes().

I think this is breaking projects like fig (can't mount volumes) or saltstack dockerio module:
docker/compose#622

Code example reproducing issue for me:

from pprint import pprint
from docker import Client
c = Client(base_url='unix://var/run/docker.sock')

res = c.create_container('busybox', name='pytest', detach=True, 
    command='sh -c "while true;do echo test;sleep 1;done"',
    volumes=['/mnt/test',])
binds={
    '/test':
        {
            'bind': '/mnt/test',
            'ro': False
        },
    '/var/www':
        {
            'bind': '/mnt/vol1',
            'ro': True
        }
}
# start
c.start(res['Id'], binds=binds)

# inspect container
pprint(c.inspect_container(res['Id'])['Volumes'])

#result
{u'/mnt/test': u'/var/lib/docker/vfs/dir/3727ff0ae94652889ad5d1095b38c62fe24defd0aa952787cf1e1b0b6b04faf7',
 u'/mnt/vol1': u'/var/www'}

You can see as /var/www is correctly bind-mounted, but /mnt/test is not. The difference is that /mnt/vol1 was not specified in volumes parameter to c.create_container()

Do you think is a docker-py issue with newer docker engine?

[cpuguy83]

This shouldn't be an issue on < 1.4
In 1.4 passing in HostConfig (ie, bind mounts, volumes-from, other host specific things) on start is deprecated... that said you can still pass in hostconfig on start.
.. However, in 1.4 volumes are now created when at container creation instead of on container start... so if the Binds parameter is not passed in on create, the bind-mounts are not created.

[bercab]

.. However, in 1.4 volumes are now created when at container creation instead of on container start...
so if the Binds parameter is not passed in on create, the bind-mounts are not created.

Are you sure? , In my example, binds parameter is passed on start(), not on create_container(), and it works.

Any way, seems clear that API does not work as stated on docs, at least with docker v1.4

[cpuguy83]

I'm writing some tests for this right now on the docker side.
But I'm pretty sure that if a volume was passed into the create command (without specifying the binds in the HostConfig), if you then pass the Binds parameter on start, it will be ignored, since a volume would already be initialized for the given volume path.

[bercab]

Yes, I agree, this is what happens in my test.
But also, I see that if you don't specify volumes nor binds to create(), and only pass binds to start(), it works (see /mnt/vol1 in example above)

Confirmed, only happens in docker >=1.4 , I have modified my issue description, sorry.

[cpuguy83]

I'm going to work on a fix on the Docker side since this was an unexpected breaking change.
However, docker-py should definitely be updated to pass all container configuration on create.

[dnephin]

@cpuguy83

In 1.4 passing in HostConfig on start is deprecated

It sounds like it's actually been removed entirely, not just deprecated

[cpuguy83]

No, just deprecated. The issue is with the volume initialization.
I'll have a PR up momentarily that fixes this on the Docker side.

[dnephin]

@cpuguy83 awesome, thanks!

[cpuguy83]

Issue is detailed here: moby/moby#9628

[cpuguy83]

And it's actually not deprecated, this was bad information.

[virtuald]

+1

[ghost]

this issue also breaks ansible docker module (