Comment 2 for bug 1931758

The command I was using was simply `juju deploy ./concourse-worker.charm --resource concourse-image=concourse/concourse`. Since storage is declared in metadata.yaml I didn't think I needed to declare anything at deploy time? If I deploy with a type of filesystem in metadata.yaml it doesn't seem like I need that, but sounds like either way it would be better if we could have juju manage the storage for us. This may require some changes to the image (or possibly just inputs to the image), as currently it's doing this, from what I can tell:

https://pastebin.ubuntu.com/p/Q9yYXZj3tK/

The docker image does have losetup, but running `losetup -f --show /opt/concourse/worker/volumes.img` on the workload container (which is what the docker image seems to be trying to do) does indeed give "losetup: cannot find an unused loop device".

It sounds like what we're really want here is:

1) A way in Concourse to be able to say "if directory x is a btrfs mount point, do nothing"
2) A way in Juju to be able to set up btrfs filesystems

Alternatively, we'd want a way to say to Concourse "just use whatever filesystem is already there" :)

What do you think?