[CentOS-devel] Making EPEL available in CBS for SIG builds

Wed Apr 28 22:07:51 UTC 2021
Davide Cavalca <dcavalca at fb.com>

On Wed, 2021-04-28 at 23:15 +0200, Fabian Arrotin wrote:
> Just some links to previous threads about this :
(cut)
> So worth reading the three threads and then revisit it maybe ? :)

Thanks Fabian, this is really helpful. I actually think the proposal
you had made back then in 
https://lists.centos.org/pipermail/centos-devel/2019-July/073860.html
would work well for this, and addresses most of the concerns I've seen
raised throughout those threads.

Specifically:
- it does not require rebuilding EPEL onto CBS (which would defeat the
entire purpose of this exercise)
- it gives SIGs autonomy of decision on whether to consume content from
EPEL, rebuild it or ignore it, on a per-package basis
- because EPEL is continuously imported and versions that are consumed
are tagged, this also solves the "yum downgrade" problem -- even if
EPEL upstream moves on, older versions that were consumed in CBS would
remain available (unless one untags them explicitly)
- OTOH, if a SIG does want to track the latest versions available in
EPEL, that is also possible (e.g. Hyperscale would like this as it
would expose potential breakage early on)

One potential issue I don't have a clear sense of is the matter of
conflicting NVRs that was raised in
https://lists.centos.org/pipermail/centos-devel/2019-July/073863.html .
This is not a concern for Hyperscale as we set a custom disttag, but it
could be for other SIGs that don't do this and also rebuild packages
present in EPEL with the same NVR.

Cheers
Davide