RE: PXE failure, alway enter rescue mode

[Rob Shelley]

Alright, so I'm confused.  You say your directory structure is /tftpd, but the 
tftp server is pointed to /tftpboot.  I'm going to assume that you meant 
/tftpboot instead of /tftpd.  I don't see any issues with the xinetd config for 
tftp.  It says that the tftp server is running as root, which tells me that the 
problem is more likely a file system issue, and not a permission issue.  But, 
to be thorough, do an 'ls -l /tftpboot'.

The log file does indeed show that there doesn't seem to be any issues 
accessing normal.mod.  But, you've truncated the messages; is there an error 
accessing another file immediately following what you've posted?  If nothing is 
showing up in the log files you may need to increase the verboseness of tftpd, 
or use a packet sniffer to find out what's really going on.

I used pretty much the same command line you did.  I don't believe there's an 
issue there though.  Obviously the client is able to get the grub pxe boot file 
(xinu105.boot) and load it, or you wouldn't be getting the grub rescue prompt.  
It seems more like the files aren't complete in the /tftpboot/boot/grub/ 
directory.  It would be helpful to have a more complete listing from the log 
file to diagnose the problem.

Rob


-----Original Message-----
From: Cheng Cheng [mailto:address@hidden 
Sent: Friday, February 11, 2011 1:48 PM
To: #IS Department
Cc: address@hidden
Subject: Re: PXE failure, alway enter rescue mode

Hi Rob,

I run tftpd-hpa as daemon, the configuration file in /etc/xinetd.d/tftp is like 
that:
**************************************
# TFTP configuration
service tftp
{
        socket_type = dgram
        protocol = udp
        port = 69
        wait = yes
        user = root
        server = /usr/sbin/in.tftpd
        server_args = -s /tftpboot
        disable = no
}
**************************************

My directory structure is like that:
**************************
/tftpd
----/boot
--------/grub
------------*.mod
------------*.lst
----xinu105.boot
***************************

When I try to use PXE to boot a machine, the machine enters rescue mode. 
*****************************************
Welcome to GRUB!

error: file not found.
Entering rescue mode...
grub rescue>
******************************************

But the log in /var/log/daemon.log shows that:
************************************************************************
Feb 11 10:34:27 server tftpd[4924]: tftpd: trying to get file: xinu105.boot
Feb 11 10:34:27 server tftpd[4924]: tftpd: serving file from /tftpboot
Feb 11 10:34:27 server tftpd[4926]: tftpd: trying to get file: xinu105.boot
Feb 11 10:34:27 server tftpd[4926]: tftpd: serving file from /tftpboot
Feb 11 10:34:27 server tftpd[4928]: tftpd: trying to get file: 
/boot/grub/normal.mod
Feb 11 10:34:27 server tftpd[4928]: tftpd: serving file from /tftpboot
*************************************************************************

However, when I test the TFTP Server, I type (on the same machine that use PXE 
boot): 
******************************************************************
$: tftp -v 192.168.2.50 -c get /boot/grub/normal.mod
Connected to 192.168.2.50 (192.168.2.50), port 69
getting from 192.168.2.50:/boot/grub/normal.mod to normal.mod[netascii]
Received 42263 bytes in 0.2 seconds [1545265 bit/s]
******************************************************************
And the log shows that:
**************************************************************************
Feb 11 10:40:24 server tftpd[4980]: tftpd: trying to get file: 
/boot/grub/normal.mod
Feb 11 10:40:24 server tftpd[4980]: tftpd: serving file from /tftpboot
**************************************************************************


It seems grub can send the correct request to the server and the server 
responses correctly. But I do not know why grub still say "file not found".

Can you send me your command to generate your pxe-image and a sample of your 
pxe-image?

Thanks a lot!

Cheng


----- Original Message -----
From: "#IS Department" <address@hidden>
To: address@hidden
Sent: Friday, February 11, 2011 12:29:29 PM
Subject: RE: PXE failure, alway enter rescue mode

Can you post the log and a list of your directory structure?  If the
prefix really is (pxe)/boot/grub then grub will look for
(pxe)/boot/grub/normal.mod and there should be a request in the tftp log
for /boot/grub/normal.mod which corresponds to
<wherever_your_tftpboot_is>/boot/grub/normal.mod on the local
filesystem.  For Ubuntu 10.10 the default folder for tftp-hpa is
/var/lib/tftpboot, so all your grub files should be under
/var/lib/tftpboot/boot/grub/.  Based on what you said, it's looking for
/normal.mod which would correspond to /var/lib/tftpboot/normal.mod,
which I'm guessing isn't there, hence the error message.  I don't
believe that it would have gone into rescue mode if it had actually been
able to access normal.mod.

The default configuration for tftp-hpa under Ubuntu 10.10 should be
sufficient to get pxe booting set up and running.  Depending on what
your end goal is you may have to tweak the settings from there.  The
permissions need to be at least read (and execute for directories) for
whatever user tftp is running as.  For Ubuntu 10.10 the default is to
run as tftp, so make sure the tftp user has sufficient permissions.

I'm not using grub 1.99rc1.  My distro was using grub legacy, so I tried
compiling grub 1.98 from source first.  It worked, so there was no
reason for me to run the release candidate.

Rob


-----Original Message-----
From: Cheng Cheng [mailto:address@hidden 
Sent: Thursday, February 10, 2011 10:00 PM
To: #IS Department
Subject: Re: PXE failure, alway enter rescue mode

Hi Rob,

I really really appreciate your reply. -:)

I use ubuntu 10.10 and tftpd-hpa as my TFTP server, and I turned on the
logging.  And the log show that grub has already download the module it
needs(normal). But I found the file name grub used is strange. There is
a "/" before the actual file name. For example, if I want to load
normal.mod, the log will shows: trying to get /normal.mod, which will
lead to fail. I do not know how to configure the TFTP to make both
/normal.mod and normal.mod work.

Can you send me your configuration file for TFTP, along with the
commands that you set up the privilege of "tftpboot" folder? And, do you
currently use 1.99rc1?

Thanks a lot!

Looking forward your rely. 

Regards,
Cheng



----- Original Message -----
From: "#IS Department" <address@hidden>
To: address@hidden
Sent: Thursday, February 10, 2011 7:03:25 PM
Subject: RE: PXE failure, alway enter rescue mode

The prefix looks fine to me (I used an identical command line for my
working setup).  My guess is the tftp server directory isn't set up
correctly.  I suggest you turn on logging (if your tftp server supports
it) to find out exactly what file is being looked for, and compare that
to the actual directory structure.  If your tftp server doesn't support
logging, then use a packet sniffer to see why the specified file is not
found.

Rob


-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of Cheng
Cheng
Sent: Friday, February 04, 2011 8:43 PM
To: address@hidden
Subject: PXE failure, alway enter rescue mode

Hi all, 

I want to use PXE to boot GRUB. And I already have grub1.99rc1 on my
computer.

The command I used to produce the pxe image is:
   grub-mkimage --fromat=i386-pc-pxe --prefix='(pxe)/boot/grub'
--output=pxe.boot pxe pxecmd

But every time, I can only enter rescue mode. The error shows "file not
found"

I think this is because the prefix has some problem, and grub cannot
resolve the path on tftp.

Can anyone tell me how to correctly set the prefix? I would really
appreciate it.

Cheng

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