Possible to force network configuration for boot=nfs?

[Andy Smith <andy@strugglers.net>]

Hello,

I'm investigating using debian-live to provide a "rescue"
environment running under Xen, with an NFS root. I'd rather not use
PXE and DHCP to configure the network of the client, because I
already have all the network settings of the client to hand.

I'm getting stuck at the client's network configuration stage
though, and it may be the case that debian-live doesn't support this.

Here's what I've tried so far.

I built a netboot binary image on squeeze:

    $ cat auto/config
    #!/bin/sh

    lb config noauto \
        --architecture              "i386" \
        --binary-images             "net" \
        --linux-flavours            "686-bigmem" \
        --packages-lists            "rescue" \
        --hostname                  "rescue" \
        --net-root-path             "/srv/rescue" \
        --net-root-server           "192.168.80.243" \
        --verbose \
        "${@}"

Resulting binary-net.tar.gz unpacked to /srv/rescue, set up my
nfs-kernel-server, confirmed that /srv/rescue can be mounted from another
machine.

I copied the kernel and initrd out of the tftpboot/ directory onto
the dom0 so Xen can boot it.

On a test client, the Xen domU configuration looks a bit like this:

    memory          = 512
    name            = 'test1'
    vif             = [ 'mac=00:16:5e:00:00:51, ip=192.168.83.104, vifname=v-test1' ]
    disk            = [ "phy:vg/test1_xvda,xvda,w",
                        "phy:vg/test1_xvdb,xvdb,w" ]
    kernel          = '/boot/vmlinuz-2.6.32-5-686-bigmem-rescue'
    ramdisk         = '/boot/initrd.img-2.6.32-5-686-bigmem-rescue'
    extra           = 'root=/dev/nfs ip=192.168.83.104::192.168.80.1:255.255.248.0:rescue:eth0:none boot=live nfsroot=192.168.80.243:/srv/rescue,tcp'

On booting that, it initially seems fairly normal, but it always
reaches this point before getting stuck:

    [    0.340547] Initialising Xen virtual ethernet driver.
    Begin: Loading essential drivers ... [    0.510610] device-mapper: uevent: version 1.0.3
    [    0.511702] device-mapper: ioctl: 4.15.0-ioctl (2009-04-01) initialised: dm-devel@redhat.com
    done.
    Begin: Running /scripts/init-premount ... done.
    Begin: Mounting root file system ... Begin: Running /scripts/live-premount ... [    0.597730] Uniform Multi-Platform E-IDE driver
    [    0.599256] ide_generic: please use "probe_mask=0x3f" module parameter for probing all legacy ISA IDE ports
    [    0.599346] ide_generic: I/O resource 0x1F0-0x1F7 not free.
    [    0.599360] ide_generic: I/O resource 0x170-0x177 not free.
    Waiting for ethernet card(s) up... If this fails, maybe the ethernet card is not supported by the kernel 2.6.32-5-686-bigmem?
    FATAL: Error inserting ide_generic (/lib/modules/2.6.32-5-686-bigmem/kernel/drivers/ide/ide-generic.ko): Device or resource busy
    done.
    IP-Config: eth0 hardware address 00:16:5e:00:00:51 mtu 1500 DHCP RARP

Now, I've booted Xen domUs with NFS root before, and normally at
this point it picks up the network settings from the ip= part and
carries on. I can't get debian-live to do that.

Do I need to do this another way, or is it simply not supported?

Cheers,
Andy