We were using Debian but Alpine more consistent. Use nested build.
Currently extract the hash in a nasty way but this can be fixed later
when we switch over hashing method.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
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>
This is needed for cloud environments that want to get their metadata in
the onboot phase over the network.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>