The shared file system aspect is an interesting wrinkle to the problem.
Unless you use some network layer to how you write to the shared file
system, e.g. SSHFS, I think apps will not work because they get isolated to
run in a container, they're given a chroot "jail" for their file system,
and it gets blown away whenever the app is stopped or restarted (which will
commonly happen, e.g. during a rolling deploy of the container-runner VMs).

Do you have something that currently works? How do your VMs currently
access this shared FS? I'm not sure BOSH has the abstractions for choosing
a shared, already-existing "persistent disk" to be attached to multiple
VMs. I also don't know what happens when you scale your VMs down, because
BOSH would generally destroy the associated persistent disk, but you don't
want to destroy the shared data.

Dmitriy, any idea how BOSH can work with a shared filesystem (e.g. HDFS)?

Amit