On 05/07/2015 02:55 PM, Jim Campbell wrote:
> Hi Vinod,
>
> On Thu, May 7, 2015, at 02:36 PM, Vinod Gupta wrote:
>> CMS is one of about twenty Physics groups here in Princeton University.
>> We have our own Linux distribution based on RHEL with a few Princeton
>> specific home grown RPMs. The CMS group has been using SL. We are trying
>> to find a most practical way of providing a "SL" environment on top of
>> RHEL based Linux without having to change the base distribution for the
>> other 19 groups in the department. I guess Princeton is not the only
>> University that has and want to maintain their own Linux distribution.
>>
>> Since both PU and SL are based on RHEL, I believe, there is lot more
>> similarity than differences in the two distributions. Can we simply
>> setup workstations of CMS group using PU linux and then install a few SL
>> RPMs to convert them to SL? Will it work for CMS work or there are some
>> fundamental changes which make SL very different, and probably
>> incompatible with RHEL?
>>
>> Thanks,
>>
>> Vinod Gupta
>> Physics department
>> Princeton University
> It sounds like you're wanting to know how different SL is from RHEL. I'd
> suggest taking a look at the SL Release Notes [0] that correspond to the
> version(s) that you use to derive your PU distribution. The release
> notes cover packages that are added to SL that aren't in upstream,
> packages that are modified, and packages that are removed.
>
> On the whole, I'd be very wary of mixing and matching repositories and /
> or arbitrary packages, but if you decide that you can manage it, the
> release notes should at least be a good starting point. Feel free to
> follow-up with the list if you have other questions.
>
> Also, thanks to the SL team for making it clear how they diverge from
> upstream.  :)
>
> Jim
>
> [0]
> http://ftp.scientificlinux.org/linux/scientific/7.0/x86_64/os/sl-release-notes.html

Thanks Jim!

On top of that, for the very curious, we try to include the patches we 
apply to the SRPMs in the SRPMs themselves for a clear explanation of 
exactly what was changed.

For example, http-2-4.6-31.sl7.src.rpm includes:
httpd-sl_index.html.sl.patch
httpd-spec_sl_index.html.sl7.patch

in the hopes that this helps clarify specifics for highly technical users.

Pat

The source for our automated patching tool can be found at: 
https://cdcvs.fnal.gov/redmine/projects/python-rpmpatch

-- 
Pat Riehecky
Scientific Linux developer

Fermi National Accelerator Laboratory
www.fnal.gov
www.scientificlinux.org