How to add packages in image tested by LAVA

[montjoie]

We boot a modified stage3 rootfs in LAVA.
But for the moment, appart adding modules, we modify only minor things (password, serial, etc..).

But some tests (LUKS for example) will need packages to be added to roofs.
Adding or compiling them in the postprocessing docker is impossible (for non-x86).

So the solution is to add only portage tree and binary packages ready to be added at run time.

Constraints:

• We cannot use a shared volume, LAVA and build are on different host
• We cannot use network filesystem (kernel could not support or need more package for it)

proposition 1:
For compiling them, we could use the "qemu-user native" gentoo docker already running for generating libelf, bc for kernel compilation.
They will periodically generate binary package necessary for tests in a volume dedicated for binary package.
This volum will be hosted in a web server
So we will need to use a pkgbin web server.