[Techtalk] kernel upgrades

[Telsa Gwynne]

On Thu, Oct 11, 2001 at 03:23:31AM -0400 or thereabouts, wolf wrote:
> Having never done a kernel upgrade, I'm using red hat 7.1, I would be
> very grateful if someone would list
> the steps to doing so or perhaps offer up a link they followed to learn
> how to do this?

The first two questions are: 
	* are you just upgrading to the latest RH-provided one, 
or are you intending to build your own in order to get support 
for something that's not included by default? 
	* are you going to try to stick to rpms or are you going 
to use a tarball?

If you just want a "working as before" kernel for RH and your
previous one was a standard RH-provided one, then perhaps you
might just want the errata kernel that came out for RH 7.1.

To get that, you have two choices. The "up2date" program is
actually usable these days and will just download it for you. 
Or you can grab it yourself from the support section of the
website: 

	http://www.redhat.com/support/errata/
	http://www.redhat.com/support/errata/rh71-errata.html
	http://www.redhat.com/support/errata/RHSA-2001-084.html

That final url says two important things: "get previous errata
installed first"; and "see this URL for how to upgrade kernels
the RH way":

http://www.redhat.com/support/docs/howto/kernel-upgrade/kernel-upgrade.html

(Well, it doesn't say "the RH way", but that's what it means :)) 

So that's one answer: get the RH one and drop it in place.

If you need to build a kernel to get support for something or
turn some option on, then normally the process is to get the
sources and build it yourself. You can still make an rpm, although I
am not quite sure how you install the result. For an rpm, you 
would need to get a recent "-ac" kernel, one of Alan Cox's kernels. 

Whether you do the "make rpm" thing or not, you'll need to read the 
docs which tell you about "menuconfig" and  "make deps" and all 
the other things you only need to know about for kernels. Having 
said that, if it's the first time you've built a kernel, it's 
probably simpler to try it the way everyone else does it and leave
fancy touches like creating an rpm for another time.

Kernel-building sounded terribly hard to me. I sat down with the
Kernel-HOWTO and still nearly messed it up: if you select anything
as "M" when going through the configuration stuff, you _must_ do
"make modules" as part of the building process, and the HOWTO 
doesn't make this at all clear (or I didn't think so, at least).
But other than that, the steps are actually pretty easy. So
long as you don't replace the old kernel until you know the new
kernel works, you can mess up kernel-building as much as you
like :) After I built one for the first time, I went through a
"oh, _that's_ what it's all about" phase and built half a dozen
more in a week. Just because :) And then I got bored of it, and
never bothered again until I specifically needed something a 
month or so ago. 

The Kernel-HOWTO everyone talks about is part of the Linux 
Documentation Project and thus lives at 

	http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html

(but you may very well want to use a more local mirror: they are
listed on the site). There are lots of other guides to kernel-
building, and there have been some nice ones posted to this list
in the past.

Everyone else is already covering the "things to know/do/try if
you build your own" so I'll stop. I just thought it worth mentioning
that if you just want a newer one, then RH does have some which 
should just work. I have used up2date to grab kernels before and
it worked the time I tried it.

Telsa