Re: Bringing substitutes from the Guix Build Coordinator to users

[Mathieu Othacehe <othacehe@gnu.org>]

Hey Chris,

> That sounds sensible. On the specific name, given this is just about
> substitutes, and at least in my opinion has nothing to do with
> continuous integration, maybe picking just another word would avoid
> thinking too much, it could be bordeaux, or hippo, or anything
> really. As you say, stability and not being tied to a particular machine
> is the important thing.

The substitutes coverage is one indicator to take into account but there
are many others. For instance, the evaluation speed, the failed
evaluation count, the average evaluation builds completion time, the
availability of the connected build machines between other things.

Deploying a solution that builds substitutes is fine, but as soon as it
is deployed and accessible to all Guix users, the system administrators
will have to monitor it and maintain it in the long run.

Having two heterogeneous build infrastructures on two sets of machines,
providing different metrics will make the update and maintenance of
those machines harder.

I hear your point about K-out-of-N policy and it also makes sense to
me. However, we should maybe consider doing it using two similar
infrastructures.

Thanks,

Mathieu