[TriLUG] BOOTP and Kickstart

[Timothy A. Chagnon]

On Tue, 2005-06-21 at 15:24, Roy Vestal wrote:
> Hey guys, is there a way to start a "kickstart" install from a 
> command line? i.e. I've booted a server to a bootp to my network. I do
> not have privs to add the kickstart info to the bootp/dhcp server.

>From command line... Do you mean the boot: prompt?  This would imply
that the dhcp server you are using is already set up to send a TFTP
server IP and filename to get.  Maybe a clarification of this process
would help...

1. PXE agent on NIC card does a DHCP request.
2. DHCP server sends std response plus has a couple fields 'next-server'
and 'filename'.  These are the bootp extensions to DHCP and specify a
TFTP file to get and which server to get it from.  If next-server is
empty, PXE should try the same IP as the DHCP server.
3. PXE agent downloads and runs the file (bootstrap program, usually
pxelinux.0 from syslinux or elilo).
4. bootstrap program then can display boot: prompt to pick a
kernel/initrd which it also gets from tftp server.  In pxelinux there is
a config file on the tftp server which can specify different kernels and
options like ks=...  But of course this option only applies to an
anaconda (RH/FC installer) kernel/initrd.
5. kernel boots...
6. In the case of an anaconda kernel/initrd, it will at some point want
to start the NIC, at which point it will DHCP again.  Some dhcp server
configurations look at the request for client type (pxe or non-pxe) and
will at this point send the filename field set to the kickstart file (on
a http server) instead of the pxe-bootstrap program.

So I guess the point is, it all depends on what bootstrap program and
resulting kernel your DHCP server is sending you?

Tim
-- 
Timothy A. Chagnon
<tchagnon at futeki.net>, <tchagnon at nc.rr.com>, <tchagnon at unc.edu>
Linux, how do I love thee? Let me count the ways: while(1){count++;}