[Beowulf] Gentoo in the HPC environment

[Jason Riedy]

And Joe Landman writes:
> Which means one of a few options
> 1) stateless as I had mentioned: [...]
> 2) VM based: [...]
> 3) Docker/Container based: [...]

There's a possible bonus to having an image available (even if it
wraps a container of a different image).  Up to some commercial
software licenses, you can relieve the front-end nodes of a bit
of load.  You provide an image that matches the machine
sufficiently well that binaries can just transfer and run on the
real thing.  Then users can run the build/modify/build cycle
locally.  If they have small enough tests, possible even
kinda-parallel tests locally.

(Likely also needs compiler wrapper scripts to target the right
chip rather than using -march=native, but that's relatively
minor.)

Very handy approach we *might* try someday for students,
particularly those in remote or massive on-line courses...