[CentOS-devel] How Centos compiles SRPMs from Red Hat

Sat Apr 7 11:10:36 UTC 2012
Johnny Hughes <johnny at centos.org>

On 04/06/2012 06:33 PM, Peter Penzov wrote:
> I have some questions to ask:
> 1. What build server do you use and how is configured? Can you paste the
> mock configuration? (If you use mock)
> 2. How much time is necessary to build the complete OS?(all packages)
> 3. When you download the SRPMs from Red Hat ftp server how do you remove
> the old packages from the latest?
> 4. Are there any hidden stones?
> Please share

Don't top post ... it is annoying and is not per our guidelines.


Our guidelines are here:



Karanbir answered the rest of the questions ... but here is an answer to
the one about how long (your #2):

We have no idea how long it would to take to rebuild everything.  We
don't do that except for the first time we build a release.  We don't
even have any idea if the current SRPMS would build right now if you
tried it (although the SHOULD).

This is because we don't rebuild everything on every run.  We only
rebuild NEW things as they are released.

So, upstream releases 3 SRPMs today and we rebuild them today.  They
release 3 more SRPMS tomorrow and we rebuild them tomorrow, etc.

So our rebuild is Staged ... if you take all the SRPMS and rebuild them
all at the same time then that may or may not work and may or may not
produce identical results.

For example, things that remain from the original CentOS-6.0 build were
built against the repositories as they existed at that point in time.
If you rebuild them now against CentOS-6.2 (as it exists now), that
could introduce some inconsistencies as you would be using a different
gcc and glibc (the new ones not the 6.0 ones).


Also, please note that the "CentOS Linux" distribution is open source
and we (the "CentOS Project") provide all source code as we build it.
(That would be the items from the SOURCE directories when you extract
the SRPMS).

We also provide all the scripts and methods required to rebuild it (that
would be the SPEC file and rpmbuild and our distro, if you install it).

Our goal is to provide you will a distribution that is free to use and
to provides sources as required by the licenses of the software that are
contained in CentOS.  You provide your own support, although you can use
our mailing lists, forums, and wiki to get help from others in the
"CentOS Community".

However, it has never been the intent of the "CentOS Project" to tell
you how to reproduce CentOS ... we just to provide the things we need to
provide because we are Open Source.

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