Re: Questions regarding offloading ( unprivileged setup , parallel builds )

[Ludovic Courtès]

Hello,

YOANN P <address@hidden> skribis:

> I didn't find any documentation describing a way to use an alternative file 
> for the offload settings instead of the default /etc/guix/machines.scm.
>
>
> Did i missed something ?

No, this is correct.

> Is there other files that are put under /etc ?

/etc/guix also contains things related to substitutes.

> It could be problematic for users who use custom store/state path in 
> unprivileged environnements but want to use the offload isn't it ?

Indeed, though if you’re customizing things anyway, you could run:

  ./configure --prefix=/my/prefix --sysconfdir=/my/etc

> Another question regarding the offload, how are used the machines describe 
> inside  /etc/guix/machines.scm ?
>
> If the installation of a package require to build multiple packages, does the 
> builds are all done on the first machine choose for the build or distribute 
> over all machines describe on /etc/guix/machines.scm ?

When there are several matching machines, ‘guix offload’ currently picks
one at random; if that machine is already under high load, it goes on
and picks another one.  See:

  https://git.savannah.gnu.org/cgit/guix.git/tree/guix/scripts/offload.scm#n442

> The description of "parallel-builds" parameter and the fact than missing 
> dependencies already present on the host who request the offload seem to be 
> transferred through ssh let me think that only one machine at time is used 
> for the offload even if all the machines present inside machines.scm share 
> the same store.

Several machines can be used at the same time, no worries.  :-)

> Not sure about this too, there is no ssh transfert if the dependencies (same 
> packages / store path ) are already on the offload store isn't it ?

Right, only missing items are transferred.

> Implementing something similar to the project "guix-relocate" from Pjotr 
> inside the core project to be able to use native Guix packages with custom 
> path when we install them would be a real huge improvement to prevent the use 
> of proot/namespace/offloading :)

I think offloading serves a completely different purpose: it’s a way to
distribute builds to several machines.

But yeah, we discussed relocation at FOSDEM again and it’s a useful
thing in its own right, even though there are limitations.  :-)

Ludo’.