[syslinux] Chain loading to another PXE server?

[Pierre Neyron]

Carl Karsten wrote:
> H. Peter Anvin wrote:
>> Mike Dorman wrote:
>>> Is it at all possible to chain load to another PXE server using
>>> pxelinux?
>>>
>>> I'm wondering because we are getting ready to roll out a new dedicated
>>> server provisioning system at the datacenter where I work.  In the past
>>> we've used pxelinux to network boot the Linux installations (e.g.
>>> anaconda.)  We also use it to network boot to rescue mode, memtest86,
>>> etc.
>>>
>>> But we are moving to a new product called Snap Deploy from Acronis.
>>> It's an imaging tool similar to Ghost which will allow us to provision
>>> servers by applying an image to them, rather than having to wait for
>>> Linux or Windows to install and then manually doing all the
>>> configuration.
>>>
>>> The drawback is that it only works with its own (proprietary) PXE
>>> server.  But we still want to keep our pxelinux system around for
>>> booting resuce mode, etc.
>>>
>>> What I'd like to do is have one boot option in pxelinux be "Boot to
>>> Acronis Snap Deploy" which would then direct the machine to the Snap
>>> Deploy PXE server and boot with that one as normal.
>>>
>>> But from what I've seen, there is no way to do this.  Is that correct,
>>> or am I missing something somewhere?
>>>
>>
>> There is no way to do this.  There isn't really any meaningful way 
>> this could be done (because of the discovery phase), except possibly 
>> via vlans.
> 
> 
> label Acronis
>         kernel memdisk
>         append AcronisBooter.img
> 
> where AcronisBooter.img is made from
> 
> http://rom-o-matic.net/5.4.2pre2/
> 

Another way of *uglily* get this done, is to hard-code the tftp server 
IP address in a modified pxelinux.0 binary. Then this 
pxelinux-tftpd-forced.0 was chained by the original pxelinux.0 (but may 
also be chained by another PXE bootstrap that support chaining) and was 
short cutting the tftp server given by DHCP.
This obviously needs some good knowledge of ASM.
We had to do this some time ago and it was working well (I said ugly, do 
I ?;) )

Regards
-- 
Pierre NEYRON