systemd-sysext can load a raw-image containing usr/ and opt/ folders
to mount them as RO overlay over the rootfs, to "extend" the systems.
This class provides the necessary changes/additions to the enclosed
filesystem so that systemd-sysext accepts the extension for "merge"
into the rootfs.
With such a created image, placed into the correct folder (see [1]),
`systemd-sysext list` should be able to list the "extension" and
`systemd-sysext merge` should enable the overlay. On both commands a
preceding "SYSTEMD_LOG_LEVEL=debug" can aide in figuring out what is
amiss.
Link: https://www.freedesktop.org/software/systemd/man/latest/systemd-sysext.html
Link: https://0pointer.net/blog/testing-my-system-code-in-usr-without-modifying-usr.html
Signed-off-by: Johannes Schneider <johannes.schneider@leica-geosystems.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
