[gPXE] Problem using gPXE to load PXELINUX with HTTP server

[Allan Wu]

Hello,

I got a problem of starting PXELINUX with gPXE using HTTP server. I am
trying to setup a diskless system using gPXE. I intend for all the client
machines to use static IP in the network, and our network already have a
DHCP server which is difficult for me to modify. So I want to use gPXE to
assign static IP for my client machine and obtain image from a HTTP server.

In gPXE, I can successfully load the pxelinux.0 file and execute it.
However, PXELINUX then reported an error saying "Unable to locate
configuration file". I tried with several versions but got similar
problems.

In general, I want to set each client with static IP to get around the DHCP
server, which seems to work for getting the images. I also tried to load
the initrd image and vmlinuz kernel directly. But I got error saying the
kernel cannot find ramdisk. I think I need to use the parameters such as
'initrd=' and 'root=' when booting the kernel. Is there a way to do that
with gPXE along? I'm open to other alternatives, since my approach may be
limited on my lack of knowledge.

My setup looks like this:

- On the HTTP server:
http://xxxx.xxx.xxx/xxx/tftpboot/ ~ this is the root directory for the
pxelinux file
./pxelinux.0
./pxelinux.cfg/default
./centos6/ ~ this directory contains the ramdisk
image and kernel

The pxelinux configure file looks something like this:

default rhel6
label rhel6
kernel centos6/vmlinuz
append initrd=centos6/diskless_initrd.img
root=nfs:xxx.xxx.xxx.xxx:/diskless/x86_64/RHEL6/root/ rw

- For my client, I embedded a static.gpxe script looks something like this:
#! gpxe
ifclose net0
set net0/ip xxx.xxx.xxx.xxx
set net0/netmask xxx.xxx.xxx.xxx
set net0/gateway xxx.xxx.xxx.xxx
set net0/dns xxx.xxx.xxx.xxx
ifopen net0
set 209:string pxelinux.cfg/default
set 210:string http://xxx.xxx.xxx/xxx/tftpboot/
chain ${210:string}pxelinux.0

After this the PXELINUX is booted, but then failed on the error. I was
using PXELINUX 4.02. For newer version, I also tried 5.10, but then
PXELINUX stucks on the first line (version and copyright stuff).

I can attach some screenshot of the error message if needed. Please tell me
if I need to provide more information.

Thanks in advance!

Regards,
--
Di Wu (Allan)
Center of Domain-Specific Computing <http://www.cdsc.ucla.edu/>,
Department of Computer Science, UC Los Angeles
Email: allwu at cs.ucla.edu
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[Gene Cumm]

Post by Allan Wu
Hello,
I got a problem of starting PXELINUX with gPXE using HTTP server. I am
trying to setup a diskless system using gPXE. I intend for all the client
machines to use static IP in the network, and our network already have a
DHCP server which is difficult for me to modify. So I want to use gPXE to
assign static IP for my client machine and obtain image from a HTTP server.
In gPXE, I can successfully load the pxelinux.0 file and execute it.
However, PXELINUX then reported an error saying "Unable to locate
configuration file". I tried with several versions but got similar problems.
In general, I want to set each client with static IP to get around the DHCP
server, which seems to work for getting the images. I also tried to load the
initrd image and vmlinuz kernel directly. But I got error saying the kernel
cannot find ramdisk. I think I need to use the parameters such as 'initrd='
and 'root=' when booting the kernel. Is there a way to do that with gPXE
along? I'm open to other alternatives, since my approach may be limited on
my lack of knowledge.
http://xxxx.xxx.xxx/xxx/tftpboot/ ~ this is the root directory for the
pxelinux file
./pxelinux.0
./pxelinux.cfg/default
./centos6/ ~ this directory contains the ramdisk
image and kernel
default rhel6
label rhel6
kernel centos6/vmlinuz
append initrd=centos6/diskless_initrd.img
root=nfs:xxx.xxx.xxx.xxx:/diskless/x86_64/RHEL6/root/ rw
#! gpxe
ifclose net0
set net0/ip xxx.xxx.xxx.xxx
set net0/netmask xxx.xxx.xxx.xxx
set net0/gateway xxx.xxx.xxx.xxx
set net0/dns xxx.xxx.xxx.xxx
ifopen net0
set 209:string pxelinux.cfg/default
set 210:string http://xxx.xxx.xxx/xxx/tftpboot/
chain ${210:string}pxelinux.0
After this the PXELINUX is booted, but then failed on the error. I was using
PXELINUX 4.02. For newer version, I also tried 5.10, but then PXELINUX
stucks on the first line (version and copyright stuff).

How are you loading gPXE, from floppy/ISO/USB?

For a first test, I'd suggest a different version of PXELINUX. Having
seen numerous bugfixes on syslinux at zytor.com, I'd suggest starting
with the precompiled binaries from the binary/source archive at
kernel.org and using 4.07.

If you want to try 5.1x, you can either use gPXE to load
core/pxelinux.0 via HTTP then com32/elflink/ldlinux/ldlinux.c32 (yes,
it needs that before the configuration file) OR set DHCP option 210
(direct or encapsulated) on your DHCP server and load core/lpxelinux.0
from TFTP then all other files relative to the prefix in 210. I'd
suggest version 5.11-pre9 for your first test of a 5.1x version.

Also, if you wanted to try 6.0x, either 6.02 or 6.01, either
bios/core/pxelinux.0 or bios/core/lpxelinux.0 with
bios/com32/elflink/ldlinux/ldlinux.c32