[et-mgmt-tools] Cobbler profile pxelinux text

Michael DeHaan mdehaan at redhat.com
Wed Jun 13 18:06:17 UTC 2007

Caetano, Greg wrote:
> Is it possible with cobbler to not have the "ks=" or "autoyast=" kernel
> parameters added to the pxelinux menu for a given profile? I'm trying
> have a pxelinux boot entry for a firmware update option and am running
> into too long of a line for the append parameters.
> Thanks
> Greg
> Greg Caetano
> HP TSG Linux Solutions Alliances Engineering
> Chicago, IL
> greg.caetano at hp.com
> Red Hat Certified Engineer
> RHCE#803004972711193
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> et-mgmt-tools mailing list
> et-mgmt-tools at redhat.com
> https://www.redhat.com/mailman/listinfo/et-mgmt-tools

That defeats the purpose of fully automatic installation, doesn't it? 
For PXE, the "ks=" line cannot be removed. However, yes, I think I can 
help you with your problem.

If you have an older cobbler install that you've upgraded, you probably 
have a few kernel options in /var/lib/cobbler/settings which are
not required and can be removed, but in newer installs, there aren't 
many that can be removed to save space. Current cobbler defaults to 
"lang= ksdevice=eth0 text" as default options. Also, for the last 
several cobbler releases, the kickstart arguments are shortened a good bit.

It would probably be helpful to see what arguments are on your kernel 
command line (you can obtain this by reading 
/var/www/cobbler/profiles/$filename or looking at /tftpboot/pxelinux.cfg 
-- without seeing what you have, I can't really suggest what I would 
remove or what might be specifiable in kickstart instead of the kernel 
command line.

Aside: As I mentioned above, koan doesn't use the ks= parameter for 
--replace-self. Why? Because in a lot of situations, DHCP timeouts cause 
problems, and in this case, we can help avoid them. What koan's 
--replace-self does is download the intended initrd, crack it open, and 
insert a kickstart file back into the initrd. So, technically, yes, this 
could be done in cobbler for PXE cases as well. However, there is a 
disadvantage to doing this: diskspace and long sync times. Cobbler sync 
would take about 30 seconds for each profile and system as it cracked 
open the files, and every profile and system would require storage of a 
custom initrd on the filesystem. This is very undesirable especially 
when managing thousands of systems. So, if you need to do reinstalls, 
use --replace-self, but embedding the kickstart in the initrd is not a 
good thing to perform client side. However, if this is something you are 
really interested in, patching cobbler to allow initrd managling is 
doable -- and I'd consider a patch to allow this as an option. Using it 
would require that minimize_syncs be disabled, so that synchronization 
(which would be really lengthy) could be run in batch. Anyhow, this 
isn't a super-great way to solve the length problem, and is a bit weird, 
so that's not ideal.

As I've said, as I really don't know what your kernel command line 
options are, I can't tell why they are so long ... but maybe I can help 
if you share them.

FYI -- if you can, send questions to et-mgmt-tools at redhat.com so more 
people can benefit from answers. If it's to be not showing @hp.com on a 
list, a lot of folks use gmail accounts for this kind of thing.


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