[Mageia-dev] Will this work for a build system?

Buchan Milne bgmilne at multilinks.com
Mon Sep 27 00:49:31 CEST 2010

On Sunday, 26 September 2010 18:14:15 Giuseppe Ghibò wrote:
> IMHO the idea of the cloud is not that bad

It has obviously already been thought about to some extent.

> but need to be rethinked. I
> don't see so much flaws for security. If you inspire to what repsys is
> right now, the cloud would be like having several svn repositories
> mirrored around the world each one with a local iurt/repsys building
> system (it might be even partial, e.g. there could be BIG ones holding the
> whole svn|git tree, and smaller one holding just the latest release or the
> latest two releases, etc.). Each building system around the world will
> sign packages they build with their own signing keys and you know where
> they come from. And packages won't be resigned by a supposed master. Of
> course you have to trust their administrators, exactly like you right now
> have to trust single users submitting sources to the svn and bulding
> packages.

No, at present we trust users to submit source code, that can in theory be 
audited quite easily.

Changing a distributed model means you need to trust all users who have any 
way to affect any of the toolchain on any of the hosts (taking into account 
e.g. compiler trojans), or you need mechanisms to be able to validate it the 
toolchain. While this could be done with a slow-moving distro, with a fast-
moving one, where parts of the toolchain and integral libraries change on a 
more-frequent-than-weekly basis, the manual overhead to update signed 
filesystem images or similar would probably be excessive.

Changing to a distributed, virtualised model brings in more issues (how about 
trojaned hypervisor?), while possibly allowing to mitigate some ...

What we could do in a more distributed fashion (e.g. on EC2 or similar), is 
providing instances on which developers test/develop builds (such as the 
interactive use of n*, chroot* etc. on Mandriva).

> The most difficult things IMHO would be building from the same syncronized
> data. In that case you might choose a master server and several mirrors.
> The master might have multiple internet access points (e.g. from two
> providers) and will be the only one who might receive svn commits. Or a
> model without a master, I guess inspiring to a model what UseNET is (was),
> I think a lot more complicate. But in that case you have two direction of
> feeding and if two libraries are submitted in different user in nearest
> time, you need a system to check for coerency and set alarms in some
> cases.
> IMHO one of the building problems was not massive automatic rebuilding but
> avoid bottenlecks to the users when building goes wrong.

But, there aren't usually very many cases like this which can be solved by 
distributing outside the control of the foundation. A standby build 
environment to go with a standby authoritative mirror host would be nice, but 
it would need to same security as the production authoritative mirror host.


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