Diskless PXE clients: switching FreeBSD kernels based on MAC
soekris at house.org
Sun Mar 21 14:26:32 PST 2004
I'm following up on my original question and cross-posting it to the
Soekris list in case this is useful for anyone else. If there's an
easier way to do this, I'd like to know!
Here's a bootloader script I wrote that works for me (FreeBSD
\ -- MAC-based kernel switching for PXE clients
\ Allows PXE booting of different kernels for different MAC
\ using a shared NFS root partition.
\ Will use the default kernel if not booting from PXE or no HW MAC
\ addresses are matched.
\ 1. Place this in /boot on the NFS server.
\ 2. Include this from /boot/loader.conf using the following line:
\ exec="include /boot/kern_switch.4th"
\ 3. Edit the MAC address and kernel definitions below.
\ 4. Make sure you have an alternate boot device handy when
\ so you can undo things if you make a mistake!
\ v 1.0; Mar_21_2004; Chris Roehrig <croehrig at house.org>
: switch_kernel ( kern_addr kern_n -- )
2dup ." kern_switch DBG: switching kernel to " type cr
s" kernel" setenv
\ Check environment for loaddev...
s" loaddev" getenv dup -1 = [if]
drop \ the -1 retval
.( kern_switch: no loaddev present in environment!) cr
2dup .( kern_switch: loaddev = ) type cr
s" pxe0:" compare 0= [if]
\ PXE Boot; get the hardware MAC address...
s" boot.netif.hwaddr" getenv dup -1 = [if]
drop \ the -1 retval
.( kern_switch: no boot.netif.hwaddr present in environment!) cr
2dup .( kern_switch: boot.netif.hwaddr = ) type cr
\ switch on HW address...
\ ENTER YOUR MAC ADDRESSES AND KERNEL NAMES HERE
\ Pad all MAC bytes to 2-digit, lower-case.
\ Be careful to preserve the space after s" !
2dup s" 00:00:24:c1:2a:64" compare 0= [if]
s" /kernel.NET4501" switch_kernel [then]
2dup s" 00:00:24:c1:35:50" compare 0= [if]
s" /kernel.NET4801" switch_kernel [then]
2drop \ environment HW string
\ Display the kernel to be used...
s" kernel" getenv dup -1 <> [if]
.( kern_switch: using kernel = ) type cr
.( kern_switch: no kernel present in environment!) cr
On Mar 20, 2004, at 10:58, Chris Roehrig wrote:
> I'm running FreeBSD 4.9_RELEASE and I'd like to share my server's root
> partition as the root partition for some diskless PXE clients, but I
> need different kernels for the server and clients. The /conf
> structure works great for providing different /etc environments for
> each machine, but I can't figure out how to boot a different kernel
> for my PXE clients.
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