[syslinux] Chainloading pxe boot loaders and dhcp root-path option

[H. Peter Anvin]

On 05/14/2011 09:14 PM, Matt Fioravante wrote:
> Is there anyway to set dynamically set dhcp options when chain loading
> another pxe boot loader?
> 
> I'm setting up a pxelinux network install server and one operating system I
> want to support is freebsd.
> 
> Freebsd has its own pxe loader called pxeboot that you can use. You just
> have to boot it from tftp and set the root-path dhcp option (option 17) to
> the location of your nfs server with the kernel and network filesystem.
> 
> I want to support multiple versions of freebsd (i386 and amd64) along with
> Linux distros and others. The are hackish ways to accomplish this using
> memdisk, but thats not a great idea if you want to have a 280MB live cd
> image. The most elegant way I can see to do this is to chain load freebsd's
> pxeboot loader from pxelinux. The problem is when you do this, the dhcp
> root-path option is not set and defaults to /.
> 
> I need to be able to dynamically change this dhcp option before chain
> loading into the next pxe boot loader. Essentiallly, I'd like to be able to
> do something like this:
> 
> LABEL fbsd32
> pxe pxeboot.0 dhcp-root-path=/nfsserv/freebsd/i386/root
> 
> LABEL fbsd64
> pxe pxeboot.0 dhcp-root-path=/nfsserv/freebsd/amd64/root
> 
> Is this at all possible with pxelinux?
> 

This is what pxechain.com does.  This assumes that pxeboot.0 gets the
DHCP options from memory and not by doing its own DHCP request.

	-hpa