[CentOS] Request for good advice to upgrade kernel

Tue Mar 21 14:20:31 UTC 2006
Peter Kjellström <cap at nsc.liu.se>

On Tuesday 21 March 2006 13:47, Kari Salovaara wrote:
> Hi,
>
> first I want to thank maintainers of this excellent distro. I've had no
> problems, even I'm using quite new motherboard (Asus P5WD2) and dualcore
> Intel D 820 processor. I've updated all packages when You have announced
> them. At the moment the kernel is 2.6.9-34ELsmp and it works well.
>
> But I've lost some understanding how these kernel versions flow !  I'm
> also a little confused of some related answers from some forums and
> lists. Questions :
> - is the kernel version used in CentOS the same as in kernel.org ?

As previous replies stated, it's a vanilla 2.6.9 with lots of patches 
(internal rh ones and stuff (security updates, driver updates, bugfixes) 
backported from later 2.6 kernels).

If you install the src.rpm you get to see all the gory details. Patches can be 
found in the SOURCES dir.

> - if the kernel versions don't match, where do I get information which
> mathes which ?

You don't, there is no such thing as 2.6.9-22 matches 2.6.14 etc. All you get 
is the list of patches and the (very well maintained) changelog (rpm 
--changelog) if you really really need to know.

>
> The other question (very much relates to the later part of previous
> question and the need to do kernel compilation at all) :
> - if I want to compile new kernel using kernel source from kernel.org,
> what is the best way regarding to maintain the workability level of
> exisisting kenel (see top)?

If you really need it, you can take your chances with a kernel.org kernel. My 
suggested way would be to select a kernel-2.6.x.y such that x is old enough 
for y to be large enough =). Today that would probably be 2.6.15.6.

> -- can I use .config-file from working 2.6.9-34ELsmp source and compile
> straight using that

This should work fine, I then usually do make menuconfig and make rpm

> (first to see a working new kernel and then make 
> some adjustments) ? In this way I can save a lot of time and frustration
> when setting the flags for compilation. Any other important to remember
> ? (I've compiled kernel since Linux 0.6 so no newbee recommendations. ;-) )
> -- I need monitoring for many servers (thermal etc.) and of course they
> are remote. I would like to use OpenIPMI which seems to be the most
> modern method and thus would survive for some years (not expected of
> some other methods/applications)

ipmi only works on some servers though, but when it works it's nice.

> -- these issues are important to due I've more than 1 server and I'd
> like to use similar approach in each.
>
> Could You point me a) documents to wise upgrade of kernel in CentOS 4.x
> environment ? b) if there exists, example of use OpenIPMI ?

the kernel (2.6.9-34) comes with really up to date openipmi drivers and centos 
ships with ipmitools, you're all set. Mini-howto: modprobe ipmi_si, 
ipmi_msghandler, ipmi_devintf, then you can run "ipmitool sel list" for 
example.

good luck, 
 Peter

>
> You can also send answers directly as this topic might not interest
> wider public.
>
> Best regards,
> Kari Salovaara

-- 
------------------------------------------------------------
  Peter Kjellström               |
  National Supercomputer Centre  |
  Sweden                         | http://www.nsc.liu.se
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