[CentOS] building a new kernel, problems booting without initrd

[Jim Perrin]

On 12/11/05, Richard Hubbell <richard.hubbell at gmail.com> wrote:
> Hello all,
>
> Grabbed a new kernel (from kernel.org) to build a custom kernel
> but it won't boot.  I followed the directions at redhat to setup a box without
> initrd (which I don't want and don't need to use). But the system hangs.
> Has anyone built a custom kernel without using initrd? I'm using CentOS 4.2.
> It hangs at or after "Freeing unused memory"
>
> Thanks.
>
> excerpt from the page:
> (http://fedora.redhat.com/docs/udev/)
>
> Udev without initrd
>
> Install Fedore Core as usual and reboot. Execute the following commands
>
>
> mkdir /tmp/dev
> mount --move /dev /tmp/dev
> sbin/MAKEDEV null console zero
> mount --move /tmp/dev /dev
>
> Install your kernel without an initrd. Reboot.
>
> You will get some SELinux errors, and syslogd will not work as expected.


Why is it that you feel the need to rebuild the kernel?

The centos/rhel system is built atop a very heavily patched kernel. If
you build from straight vanilla source from kernel.org, expect
breakage. There are things like selinux, nptl, etc that will break for
you, and may or may not cause apps to fail or behave erratically, the
system to hang (seems like you found that one already) etc.

basically, if you need to rebuild the kernel, you should do so from
within the most recent kernel source rpm. Anything else is going to
cause issues, and you're likely to be on your own for help.

All that negativity aside, there's a tutorial on how to rebuild
kernels via source rpm here: 
crab-lab.zool.ohiou.edu/kevin/kernel-compilation-tutorial-en/

Please. centos isn't gentoo and I'd advice not treating it as such if
it's possible. If what you need isn't in the stock kernel, then look
to the centosplus kernel. If it's not there, ask on the mailing list
or on irc. Others may need what you're after if you have a valid
reason.


--
Jim Perrin
System Architect - UIT
Ft Gordon & US Army Signal Center