Expose fuse mounted inside a docker container

Question

I'm trying to run a docker image for mounting hubic (online storage) and expose that to the host

What is working so far is container mounting the fuse point correctly (to /mnt/hubic)

When running docker I am attempting to run with volume mapped as /path/on/host:/mnt/hubic this appears to work ( ie docker makes the directory if it doesn't exist) but the contents never appear. If I enter the container I can see the files from the online storage but the host folder contains nothing

Is there an option I'm missing to allow docker to do this ?

Command I am using to start the container

docker run -v ~/.hubicfuse:/root/.hubicfuse -v /tmp/mounted:/mnt/hubic --device /dev/fuse --cap-add SYS_ADMIN --security-opt apparmor:unconfined -it {container_name}

@kamil I wish to read the files from the host. Using a shared volume. Normally inside a container you can mount a directory from inside to be a real directory on the host. Hoping this is also possible with fuse — exussum, Nov 11 '18 at 20:51
See [this answer](https://stackoverflow.com/a/43687970/165358) on using the `:shared` flag, which might also work for FUSE. — harrymc, Nov 12 '18 at 07:40

score 6 · Accepted Answer · answered Nov 12 '18 at 19:35

The solution comes from the post s3 mounted inside the container. how to expose it to the host?

In this post is described a solution using glusterFS, requiring more permissions for the container. The docker command used:

docker run --cap-add SYS_ADMIN --device fuse -v host_mount_dir:container_mount_dir:shared IMAGE COMMAND

For an error like "Path /foo is mounted on /foo but it is not a shared mount ...", the reason is that the docker daemon runs in different mount namespace than systemd. This is the solution for making it run in the same namespace:

mkdir -p /etc/systemd/system/docker.service.d/
cat <<EOF > /etc/systemd/system/docker.service.d/clear_mount_propagation_flags.conf
[Service]
MountFlags=shared
EOF

And restart the docker daemon.

A remark is that the mount is visible on the host if mounted into a directory binded by -v.

Expose fuse mounted inside a docker container

1 Answers1