[CentOS] newbie kernel question

Sat Apr 1 22:55:58 UTC 2006
Maciej Żenczykowski <maze at cela.pl>

You're missing the point... If you want to get into customizing the 
kernel, you might as well switch to another non-enterprise distribution, 
more bleeding edge and the like (fedora, gentoo, etc.).  An 
enterprise-level/class distribution is meant to work with _minimum_ 
user/admin intervention.  Compiling the kernel is not a small thing and 
can potentially affect a lot of things, this simply is NOT what you want 
to do on a system you want to be a stable server.  Furthermore a lot of 
modules can be compiled outside the kernel tree proper (I've compiled a 
few netfilter modules for CentOS this way).  And, yes, you can compile 
your own kernel, you can do it for one machine, maybe two, maybe three. 
But what happens when you start to have to administer and provide updates 
for more computers (18 in my case) - do you really want to go to the pain 
of running a kernel compilation for every single one of those machines - 
and rerunning that every two months when a kernel update comes out? 
What for, what does this give me which the centosplus kernel doesn't?
In almost all cases the centosplus kernel is the far better solution.


On Sat, 1 Apr 2006, Bogdan Nicolescu wrote:

> [sarcasm]And all this time, decade+, I though the
> ability to recompile especially the kernel was the
> main difference/advantage between a source based O.S.
> and a binary-only O.S. I don't know how you came out
> with the statistics but I have a funny feeling you are
> 100% wrong.[/sarcasm]
> Everybody should want to recompile the kernel, if not
> for the experience, but for removing the bloat.  Does
> everybody really need every chipset compiled in the
> kernel!  If the degree of dificulty of building a
> custom kernel on Centos change from the traditional
> method (make clean, make mrproper, make xconfig, etc)
> than say so, and point to an authoritative howto
> guide, if there is any.  But whatever you do please
> don't insult by deciding for 98% of us what is and
> what is not "something you really want to do".  I can
> only speak for myself, and I really want to be able to
> recompile the Centos kernel, otherwise I wouldn't
> waste my energy  asking a zillion times how to compile
> Centos' kernel.
> Second irony (from second hand information) is that
> the vanila kernel compile just fine on Centos using
> the traditional method.
> --- Maciej ?enczykowski <maze at cela.pl> wrote:
>> That's because 98% of the time recompiling the
>> kernel is not something you
>> really want to do, and the remaining 2% of the time
>> you just use
>> rpmbuild --rebuild kernel-.....src.rpm
>> And if that doesn't work _then_ you're out of luck
>> (the above works for me
>> with a couple different kernels).  Want to change
>> something?  Unpack the
>> srpm into the appropriate directories (just install
>> the src.rpm) and edit
>> the spec file and configuration files and or add
>> kernel patches to the
>> spec file, etc...
>> Of course you should do all the above as a non-root
>> user for safeties
>> sake, but that's a tad harder (need to have a good
>> macro file - here's
>> mine, although it's rather minimal and not all that
>> good:
>> ~/.rpmmacros:
>> %packager	Maciej Zenczykowski
>> %distribution	CentOS4
>> %vendor		TCS-II-UJ
>> %_signature	gpg
>> %_gpg_name	maze at tcs.ii.uj.edu.pl
>> %_gpg_path	~/.gnupg
>> %_topdir	/home/buildcentos/rpm
>> %_tmppath	%{_topdir}/tmp
>> #%_rpmtopdir	%{_topdir}/%{name}
>> #%_builddir	%{_rpmtopdir}/BUILD
>> #%_rpmdir	%{_rpmtopdir}/RPMS
>> #%_sourcedir	%{_rpmtopdir}/SOURCES
>> #%_specdir	%{_rpmtopdir}/SPECS
>> #%_srcrpmdir	%{_rpmtopdir}/SRPMS
>> %disttag	centos4
>> %repotag	maze
>> # Change default RPM query format to show ARCH
>> %_query_all_fmt
>> %%{name}-%%{version}-%%{release}.%%{arch}
>> # %_query_all_fmt
>> %%{epoch}:%%{name}-%%{version}-%%{release}.%%{arch}
>> Cheers,
>> MaZe.
>> On Sat, 1 Apr 2006, Bogdan Nicolescu wrote:
>>> Nick,
>>> The question of kernel compilation is a periodic
>>> question, and usually the answer will be anything
>> else
>>> except the process itself.  I asked the same
>> question
>>> just a couple of days ago. Don't bother wasting
>> time
>>> waiting for an answer, and start searching the
>> web.
>>> rpmbuild seems to be part of the method required
>> for a
>>> custom kernel.
>>> The irony is that for a distributions which prides
>>> itself to be a recompilation of another
>> distribution
>>> (RH) (and we're all grateful for that), the
>> process of
>>> recompiling one of the integral part of the
>>> districtution, the kernel, is one of the best kept
>>> secrets.  Why can't some just give a straight
>> answer
>>> or point to a page that has the answer?
>>> Anyway, I have searched, and found this guides
>> which
>>> might help:
> http://fedora.redhat.com/docs/release-notes/fc4/errata/#sn-kernel
>>> and
> http://www.mjmwired.net/resources/mjm-kernel-fc4.html
>>> Didn't have the time to try it out yet myself.
>> Next
>>> week sometimes.
>>> --- Nick Smith <nick.smith79 at gmail.com> wrote:
>>>> Im sorry if this is a newb question, but how do
>> you
>>>> recompile the
>>>> kernel in CentOS 4.3? I need to add reiserfs
>> support
>>>> (even though the
>>>> setup detected it) the kernel it gave me didnt
>> have
>>>> support for
>>>> reiserfs, and my entire fileserver is all
>> reiserfs.
>>>> I tried the
>>>> gentoo way, which im use to and it bombed.  What
>> do
>>>> i need to do? does
>>>> it install kernel source by default? I couldnt
>> find
>>>> any good
>>>> documentation on the subject, and this is my
>> first
>>>> RH type install.
>>>> thanks
>>>> Nick
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