We added the concept of image volumes in 2.2.0, to support
inspecting an image from within a container. However, this is a
strictly read-only mount, with no modification allowed.
By contrast, the new `image` volume driver creates a c/storage
container as its underlying storage, so we have a read/write
layer. This, in and of itself, is not especially interesting, but
what it will enable in the future is. If we add a new command to
allow these image volumes to be committed, we can now distribute
volumes - and changes to them - via a standard OCI image registry
(which is rather new and quite exciting).
Future work in this area:
- Add support for `podman volume push` (commit volume changes and
push resulting image to OCI registry).
- Add support for `podman volume pull` (currently, we require
that the image a volume is created from be already pulled; it
would be simpler if we had a dedicated command that did the
pull and made a volume from it)
- Add support for scratch images (make an empty image on demand
to use as the base of the volume)
- Add UOR support to `podman volume push` and
`podman volume pull` to enable both with non-image volume
drivers
Signed-off-by: Matthew Heon <matthew.heon@pm.me>
fc6dcd12b3