Re: [Discussion]: Metadata to consolidate and rebuild base-apt from distributed CI builds

[Baurzhan Ismagulov <ibr@radix50.net>]

On Thu, Mar 03, 2022 at 07:15:40PM +0530, vijai kumar wrote:
> If we are in agreement then we can think about how to achieve this.
> There are changes coming in soon, so the implementation should take
> that into consideration.
> 
> I am not sure if the caching part is reworked. If so having an idea on
> the design would definitely help;

Thanks Vijai for the discussion. In short, we've already started further
base-apt improvement due to a number of reasons, e.g.:

* Strict usage of base-apt for debootstrap and build-dep to ensure base-apt
  correctness in any build.

* Pluggability of debootstrap, which is necessary for multistrapping, sudo
  removal, and maintainability.

* We need to know which PN-PV is satisfiable from which location (base-apt,
  isar-apt, bitbake) in order to use Debian Build-Depends in bitbake.

python-apt provides the necessary functionality. After we have the above, more
necessary use cases become possible. E.g., storing and reusing built packages
in per-layer apt repos.

We also want to have parallel building. For us, it comes more from the CI side,
as we have 3 h for fast and 10 h for full testsuite on the latest inexpensive
hardware. The first step would be to parallelize the testcases with storing of
intermediate results in a shared location. The second step would be extending
that to individual bitbake tasks. Maybe icecc would be good enough to cover
either or both, we have to test.

Regarding your implementation proposal, I think that could be done. However,
I'd like to better understand the motivation first. Is it e.g. creating a
canonical repo for a given project? That would be easier to implement on top of
the above.

Regarding downloading time -- we had tested full local Debian mirrors and
didn't see any performance improvement of CI jobs. We haven't dug deeper, maybe
we have some parallelization killers in Isar.

Regarding the central repo for remote building sites -- in my experience, it is
very slow, our customers end up installing local replication servers.

We aim at full Debian support, be it packages, repos, or images. Debian, being
a binary server / desktop distribution and not a source-based development kit,
has a number of inflexibilities such as sudo, versioning, rules, etc.; we would
like to work towards more developer friendliness here. Bitbake and Yocto
contribute much here, and we would like to find a good working solution.

That is why we welcome this use case and would like to work on that after
understanding the details. Jan told me you already had some implementations for
this. You also mention time and costs. Could you please share the concept
behind the work so far, and which time and costs you mean? Then we could
proceed step by step while having the big picture in mind.

With kind regards,
Baurzhan.