[Novalug] Kernel Compiles

[jecottrell3 at comcast.net]

I gave one good example of why you'd want to do this...New Hardware Support. I did try and find the closest kernel to the one I replaced ... I think I chose F7 even tho F8 was out. And note that Fedora is the closest relative to RHEL.

What was more amusing was using a RHEL4 kernel on Slackware 7 and 9 servers. And it did take my colleague a week or so to get the grub/modules/startup scripts compatible with each other.

But once the system is running, most programs don't care what version they are running; the ABI is quite stable.

In both cases, we didn't use source. We started by simply merging the newer system's /boot and /lib/modules into the older distro. Either that or rpm -i --nodeps of the newer binary kernel...I can't remember.

And grub will load most any kernel/initrd combination as well.

And to paraphrase Bryan, Seriously, _never_ do this *if you care about support*. Those of us who run CentOS don't, and many of us who run RHEL at work would just as happily run CentOS if our companies would let us.

Actually, my choice would be to USE CentOS, but to pay RedHat the license fees anyway just for Being Good Guys and Making It All Possible, and for those cases where we need advice or quick answers.

JIM

----- Original Message -----
From: "Bryan J. Smith" <b.j.smith at ieee.org>
To: jecottrell3 at comcast.net, "Maxwell Spangler" <maxlists at maxwellspangler.com>
Cc: "novalug" <novalug at calypso.tux.org>
Sent: Tuesday, April 13, 2010 3:50:08 PM GMT -05:00 US/Canada Eastern
Subject: Re: [Novalug] Kernel Compiles

One word:  context

This isn't about tuning.  This is about support.  If you boot a non-
Fedora/RHEL kernel, expect missing storage and core functionality,
possibly unable to get far into stage 2 of GRUB.  ;)

Seriously, _never_ do this.  That's what the context of this was about.

The "vanilla" kernel is included in every kernel SRPM.  Comment
out patches at your own risk.  ;)


----- Original Message ----
From: "jecottrell3 at comcast.net" <jecottrell3 at comcast.net>

Actually, you can. As I stated, almost any distro will work with almost any kernel. RedHat, among others, spends a lot of effort tuning the kernel to run well.

Of course, that leaves one wondering about the vanilla kernels.

----- Original Message -----
From: "Maxwell Spangler" <maxlists at maxwellspangler.com>

On Mon, 2010-04-12 at 13:19 -0700, Bryan J. Smith wrote:
> I was waiting for someone to make this point before responding.  ;)
> 
> And in that case, I would argue that #2 is actually:  
> "2) Rebuilding the distro's packaged kernel with your choice of options and patches"

> Starting with anything but the distro's packaged kernel source is a recipe for
> integration and regression issues.  ;)

Glad you confirmed that because I was assuming the same but from an
'outsider's' view of kernel issues.

It only makes sense that something like RHEL 5.4 with Redhat additions,
subtractions and patches is going to require the source Redhat offers
and that you can't easily install a mainline kernel from the same era or
a mainline kernel with a recent release.