Introducing Guix to HPC at my institution

["Sébastien Lerique" <sl@eauchat.org>]

Dear all,

(I am reposting a question I asked on the guix-science list -- 
with a broader audience here I hope someone has an answer :) )

I am interested in introducing Guix to the HPC cluster at my 
institution, and it turns out they have user namespaces activated 
\o/. So I'm looking into getting things running as an unpriviliged 
user, to show other people how useful Guix can be (before 
approaching higher levels in the administration). Is it possible 
to install guix without being root?

I tried a few things, based on the following notes:

https://hpc.guix.info/blog/2017/09/reproducibility-and-root-privileges/
https://hpc.guix.info/blog/2017/10/using-guix-without-being-root/
http://issues.guix.gnu.org/34494

I am now following Guix's binary installation inside a user 
namespace. After decompressing the binary distribution of guix 
inside `~/local-guix`, my naïve next step was `unshare -mrf chroot 
~/local-guix 
gnu/store/mmhimfwmmidf09jw1plw3aw1g1zn2nkh-bash-static-5.0.16/bin/bash`. 
Then after setting $GUIX_PROFILE and sourcing 
`/root/.config/guix/current`, running `guix` warns with:

 GC Warning: pthread_getattr_np or pthread_attr_getstack failed 
 for main thread
 GC Warning: Couldn't read /proc/stat

So my very limited knowledge of linux namespaces is hindering my 
next steps :). A few questions:

1. Should I do anything about the first warning? About the second 
warning: should I be binding `/proc` somehow?

2. Is it possible to create build users inside the user-namespaced 
chroot?

3. Last but not least: if I can create build users inside the 
chroot (question 2.), I suppose I can then run guix-daemon 
properly. How would I go about sharing this setup with other users 
on the cluster? Ideally I would like to have a non-priviliged 
build daemon that other users can call on. (Is there such a thing 
as kernel group namespaces?)

Is this the right way to go for running guix without being root, 
or is there a better way?

Thanks for any guidance you might provide!
Best,
Sébastien