CoreOS/Docker mount propagation tests

tests

# Test 1:

# Launch data-only container in privileged mode
sudo docker run -i -t --name dataonly --privileged -v /shared ubuntu:14.04 /bin/bash
# in container:
mdir /shared/usr
mount --bind /usr /shared/usr

# Launch client container and attempt to read data from data-only container
sudo docker run -i -t --volumes-from dataonly ubuntu:14.04 /bin/bash
ls /shared/usr
# empty

# Test 2: Try to get mount to propagate to host
# Something very similar works on Ubuntu, http://s3hh.wordpress.com/2011/09/22/sharing-mounts-with-a-container/

# On host: 
mkdir /media/shared
sudo mount --bind /media/shared /media/shared                                                          
sudo mount --make-shared /media/shared                                                                 
sudo mkdir /media/shared/test

# Launch container
sudo docker run -i -t --privileged -v /media/shared/test:/shared ubuntu:12.04 /bin/bash
# In container:
mkdir /shared/usr
mount --bind /usr /shared/usr

# On host, /media/shared/test/usr is empty

Test 3: With gluster

# First container
sudo docker run -i -t --name dataonly --privileged -v /gluster ubuntu:14.04 /bin/bash
# in container
apt-get install -y glusterfs-client
mount -t glusterfs <...> /gluster

# Second container
sudo docker run -i -t --volumes-from dataonly ubuntu:14.04 /bin/bash

In test #3, from inside the second container were you able to access data in /gluster? I've tried the same setup but in my case the "/gluster" directory in the second container is empty.

As far as I can tell there is no way to directly expose a fuse filesystem mounted inside a container back to the host or other containers. I've been researching this issue for a couple days and the only "solution" would be to mount the fuse filesystem and expose it using a NFS share or similar.