Re: [Etherboot-users] pxe boot ?

[Cristian M. <cri...@on...>]

* Roy Wiseman <roy...@ya...> [25-09-05 00:32]:
 
> 
> Hello,
> 
> Thanks for this Cristian. I have been looking at the
> PXELINUX and SYSLINUX sites for hours. Unfortunately
> although I have considerable knowledge on TCP/IP and
> other sysadmin work, I cannot make sense of this. This
> is written confusingly. Maybe if I was a Linux user
> for many years, I would get this, but it's been a very
> frustrating few hours I must admit.
> 
> Here's the easy bit : I got the PXELINUX.0 file to
> boot the PXELINUX.

 The PXELINUX is in fact the pxelinux.0 file. That's what it takes.
 
> Here's the hard bit : I have not got a kernel image or
> the configuration script that would make something
> boot, and there are no examples as such. There are
> some descriptions of how to do this, mostly Linux
> oriented and kind of anti-Windows in focus with jokes
> like "if you have a Windows server and cannot fix that
> ..." and then little information on getting things
> working from a Windows box. I wish I'd worked with
> Linux for the past 10 years, but I didn't, and well, I
> just want things to work ... reams of technical data
> on UNDI and ISC DHCP 3.0 do not make this easy (I
> *obviously* don't know about UNDI and ISC, I just want
> to be able to get something working that I can learn
> from, and do something practical and useful).

You don't have to know that much of linux to use syslinux or etherboot, you
just have to understand the process.
  
> Please, I would be so grateful if someone could send
> to my private email address or point me to premade
> images for DOS or Linux and the configuration files
> that go along with them all to run from a Windows box
> with tftpd32 so that PXELINUX can boot ? Then I can
> start to play with the settings described on the
> PXELINUX page and really learn something.
> 
> I've spent some hours trying to decipher these pages
> but it's not easy with the cross-referencing between
> SYSLINUX and PXELINUX "PXELINUX operates in many ways
> like SYSLINUX. If you are not familiar with SYSLINUX,
> read the SYSLINUX FAQ first, since this documentation
> only explains the differences" etc. so it's very hard
> to get anywhere FAST.

OK, let's start by makeing some light. Syslinux started as a boot loader, used
mainly for starting linux from a floppy. It is configured from a
syslinux.cfg file located on the floppy and there you can specify what
kernel image to load and various parameters passed to the kernel. Syslinux
can be used also for makeing bootable USB media, HDD partitions (only ext2/ext3
and FAT/VFAT). For making bootable CDs you can use isolinux that functions
on the same principle, but it's configuration file is called isolinux.cfg. 
Pxelinux functions after the same principle for netbooting a PXE enabled
PC: the PC loads pxelinux.0, which takes over the boot process and tries to
read a configuration file (located in /pxelinux.cfg/default) that resides
on the tftpd server, the same location as pxelinux.0. 
 So for instance I have :
  /tftpboot/pxelinux.0 
  /tftpboot/pxelinux.cfg/default
 The configuration file (pxelinux.cfg/default) has the same syntax as
syslinux.cfg and practically pxelinux operates the same as syslinux in
regard to booting, except it takes any files it needs from the network (via
tftp). 


> All I really need are some pre-made config scripts and
> some premade images for this. I'm feeling very much
> like this is a secret club that to gain admittance to
> I have to subject myself to 10 hours of reading Linux
> documentation. Please help, if someone actually has a
> working PXELINUX, please let me know the image and the
> config script, then I can be up and running in 10
> minutes instead of 10 hours, and then I can mod and
> tweak and actually LEARN. Sometimes, to learn, it's
> important to see working examples that you can learn
> from, but I'm just as clueless as I was when I started
> looked at the PXELINUX pages, as I've got no way of
> building the image and config script to go with it at
> the moment.

 Ok, let me gave you and example: I boot a DOS image disk based on FreeDos
from the network, and I offer the user to choose from DOS and LTSP
(www.ltsp.org) with a menu (recent versions of Syslinux enable you to show
a nice menu with options of booting, please get a recent version and read
README.menu for how to use it).

Files layout (on the tftp server, serves files from /tftpboot, stripping
the directory prefix) :
 /tftpboot/pxelinux.0
 /tftpboot/pxelinux.cfg/default
 /tftpboot/menu.c32
 /tftpboot/freedos/odinBig.img

The pxelinux.cfg/default file contents: 
<file>
default menu.c32
prompt 0
timeout 0

menu title pxelinux boot menu

label rip 
        menu label RIP 
        kernel ::/rip/vmlinuz 
        append initrd ::/rip/initrd.gz root=/dev/ram0 init=/linuxrc rw

label LTSP4
        menu label LTSP 4
        kernel ::/lts/2.4.26-ltsp-2/bzImage-2.4.26-ltsp-2
        append initrd=::/lts/2.4.26-ltsp-2/initrd-2.4.26-ltsp-2.gz root=/dev/ram0 init=/linuxrc rw hda=noprobe hdc=
noprobe

label FreeDOS 
        menu label DOS
        kernel ::/memdisk 
        append initrd=::/freedos/odinBig.img
</file>

the freedos/odinBigimg is a 2.88 floppy image with FreeDos (but memdisk can
boot hdd images also) and menu.c32 is from Syslinux (please read the
README.menu file to see how you can use it).

 When booting and Pxelinux is loaded, I get to this menu:
  http://img355.imageshack.us/my.php?image=pxelinux6cu.png
from where I cand choose between LTSP, a rescue linux image or DOS.

For configuring tftp32 please follow Marty's link, I have not worked with
it. 

 I know the lack of precise documentation can be sometimes disconcerting,
but you'll get there :). 

hth,

mitu