[syslinux] testing out 6.03 network booting... (6.03-pre19)

Shantanu Gadgil shantanugadgil at yahoo.com
Mon Aug 18 02:52:20 PDT 2014

On Fri, 8/15/14, H. Peter Anvin <hpa at zytor.com> wrote:

 Subject: Re: [syslinux] testing out 6.03 network booting... (6.03-pre19)
 To: "Shantanu Gadgil" <shantanugadgil at yahoo.com>, "syslinux at zytor.com" <syslinux at zytor.com>
 Date: Friday, August 15, 2014, 5:34 AM
 > We are not ready for
 "prime-time" though.
 > Using
 the "lpxelinux.0" file from 6.03-pre19 ...
 > My RHEL5 installs,
 when  using the "http://" for kernel, initrd and
 append lines, seem to be hitting some sort of parameter
 length limit.
 > The culprit seems to be
 the long "append" line.
 > The same append line, when NOT using
 "http://" work fine. (of course the initrd and
 kernel lines don't have http://xxxxxxxxx) and so are shorter.
 > RHEL6 installs works
 fines with the long parameter lengths, http or otherwise.
 > * I'll try to
 shorten the WEB url for RHEL5 and see if it goes through.
 How long
 is the parameter length?  Really old kernels had a
 511-character limit (current kernels have a
 2047-character limit), so it
 might not be
 anything to do with Syslinux...

RHEL 5 is kernel 2.6.18.x

Here is my config with the paths/IP overwritten with other characters

--- snip ---
linux  http://aa.bbb.ccc.ddd:80/_PATH_TO_RHEL5_FILES_/vmlinuz
initrd http://aa.bbb.ccc.ddd:80/_PATH_TO_RHEL5_FILES_/initrd.img
append keymap=us lang=en_US noipv6 nomodeset biosdevname=0 selinux=0 ksdevice=eth0 method=http://ee.fff.gg.hhh:80/PATH_TO_MOUNTED_RHEL5_ISO ks=http://aa.bbb.ccc.ddd:80/_KICKSTARTS/01-aa-bb-cc-dd-ee-ff.ks
--- snip ---
What happens is that the install prompt says kickstart file could not be read (because "-ff.ks" has been chopped off)
Typing it manually and pressing ENTER makes the install go through successfully, so I don't think its a RHEL5 problem.

Whichever way I count, I could not see 511 chars. :(

The chop off is somewhere around 199-200 characters (if I copy paste the block in Notepad++)

*** For now, I have removed "selinux=0" from my config file to keep RHEL5 + HTTP happy.


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