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

Ady
Mon, 18 Aug 2014 13:26:36 -0000

> >? ?
> > 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.
>
>Regards,
>Shantanu

According to:
 https://www.kernel.org/doc/Documentation/kernel-parameters.txt

the limit for kernel boot parameters is between 256 and 4096,
including spaces.

When writing your 'append' line (using 'initrd=...'), you get to
262
characters, plus the kernel line plus one space character in between.

The "-ff.ks" (last characters in your boot command) you mentioned is
6 characters long. 262-6=256 characters.

But then you report that typing in the exact same full command, it
boots OK?

Regards,
Ady.