Previously only `/var` was `rshared` but some people need to share
mounts in `/opt` etc so let us make everything `rshared` for now.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
The sha1 tag should be sufficient to uniquely identify the image
and the sha256 versions are just very long...
Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Instead of mounting a new filesystem, revert to doing a `rw` bind.
However do not make `/` `rshared`, just `/var` as that is where we expect
filesystems to be mounted for persistence. Also only make the actual
container rootfs writeable, not the whole directory.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
