[syslinux] Re: Network Boot IP Configuration Dilemma

Jon Nalley jon.nalley at rlx.com
Mon Sep 8 12:22:50 PDT 2003


Let me go into a bit more detail on my setup...

The interface that is going to PXE is connected to a management
network.  This consists of an "image server" which is the machine which
answers the PXE request.  It also runs a web application that maintains
a database of systems that it manages.  A user can select one of these
systems using the web GUI and cause it to PXE boot into the ramdisk. 
Once in the ramdisk the system contacts the "image server" to determine
what OS image to install, how to partition the drives etc.  In order for
a system to be managed in this environment one of it's NICs must be
connected to the same network as the "image server" - that is the NIC
used to PXE boot.  Whatever other NICs that server has will not be
connected to the management network (since they are used for other
purposes and separation of the management network and production network
is desired for security and performance reasons).  So the problem is
contacting the image server using the correct NIC once in the ramdisk.

On Mon, 2003-09-08 at 13:15, Luciano Miguel Ferreira Rocha wrote: 
> Do you require that the query will be by the same interface that got the
> bootp by design, or just because the other interfaces may not be connected
> to the network or to a network with a DHCP server?

I think both - there is no telling what the other NICs are connected to
and the design of the system is such that one NIC on each server is
connected to the management network.

> If the later, then you're concerned only for the delay of going through
> the interfaces until the right is found, right?

No, they could be connected to a network with a DHCP server, but it may
not be the network that the "image server" is connected to.

On Mon, 2003-09-08 at 13:17, H. Peter Anvin wrote:
> Either do just one (after all, which one ends up doing the PXE is 
> largely abitrary), try them in parallel, or better yet, since you have 
> an asymmetric setup, try the faster one first (since that's the one 
> you'd rather use if possible.)

It is not really arbitrary since it was configured in BIOS as the first
boot device.  At least this is the case with the systems I am dealing
with.  They have onboard NICs and each one is selectable in BIOS - I
realize this won't be the case for everyone though.

> > I really like the idea of passing MAC=<mac_address> and then finding the
> > matching interface in the ramdisk though.
> 
> I might decide to support that.  It's not too complex of a change, and 
> it might be useful.
> 
> However, I'm still not convinced you're doing the right thing, and that 
> worries me.
> 
> 	-hpa

After hearing your comments and thinking about it a bit more - I think
cycling through each interface and attempting to contact the image
server might be the best bet.  Although I think it could be useful to be
able to determine the NIC from which one booted using the MAC matching
method.

Thanks,

Jon Nalley




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