[CentOS] kexec for CentOS 4?

Tony Mountifield tony at softins.clara.co.uk
Tue Mar 2 16:20:37 UTC 2010

In article <4B8D34BE.3090108 at mcclatchyinteractive.com>,
Tom Georgoulias <tomg at mcclatchyinteractive.com> wrote:
> On 03/02/2010 10:04 AM, Tony Mountifield wrote:
> > In article<4B8D1650.1060001 at mcclatchyinteractive.com>,
> > Tom Georgoulias<tomg at mcclatchyinteractive.com>  wrote:
> >> On 03/02/2010 05:10 AM, Tony Mountifield wrote:
> >>> I have a remote CentOS 4 machine on a network where I can't put a DHCP
> >>> or PXE server, and I want to do a complete reinstall. So what I want to
> >>> do is, from the currently-running system, to invoke an installation
> >>> kernel and initrd in just the same way that GRUB would, giving it a boot
> >>> command line that specifies a remote kickstart file, installation tree,
> >>> and other required info.
> >>
> >>> If not, are there any other ways to achieve what I've described?
> >>
> >> I would use cobbler and koan for this.  Once you have a cobbler server
> >> setup for the kickstart (which is super easy to do), you can use koan
> >> with the --replace-self and -k options and do exactly what you want.
> >
> > Can this be done even if I can't put the cobbler server on the same
> > network as the box I want to re-install? The information I found on
> > cobbler suggested to me that it was a tying together of DHCP, PXE,
> > kickstart and install tree. As I understand it, the DHCP and PXE/TFTP
> > servers have to be local, and also I have to have the box able to perform
> > a PXE boot. So if the box in question is remote and on a network that
> > I don't control or have any other boxes on, I suspect cobbler and koan
> > wouldn't work.
> >
> > I could well have misunderstood - I found very little detail about koan
> > apart from the command line options.
> You can use cobbler and install clients without DHCP/PXE.  When you run 
> koan, you pass in all of the normal kickstart options you would use to 
> configure a static network interface (ip, netmask, gateway, dns, 
> ksdevice, etc.).  Koan will download the kickstart config and 
> initrd/vmlinuz images you need to boot up, plus add all of the grub 
> entries you need to automatically get into the kickstart after a reboot. 
>   On your next reboot, it will choose that entry in grub, immediately go 
> into kickstart mode, and follow the config in the ks.cfg file that it 
> pulled from the cobbler server.

Cool, that makes sense - thanks! It hadn't occurred to me that I could
add a new kernel and initrd to grub.conf with the required append line,
and then just reboot. Obvious when you think about it!

Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org

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