[Dnsmasq-discuss] grub-net support

[Simon Kelley]

Sergey Spiridonov wrote:
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> 
> Hi
> 
> Short question : dhcpd has special options for grub-net[1] support, like
> 
> option grub-config code 150 = text;
> option grub-config "(nd)/grubconfig";
> 
> This allows to use grub-net for remote boot. Is there grub-net support
> in dnsmasq?
> 
> 1.
> http://debian.jones.dk/hykrion/pool-etch/sid-jones/grub/grub-net_0.95+cvs20040624-17.0.jones.1_all.deb
> 
> 
> Long explanation : I used Debian and lessdisks + dnsmasq for remote
> boot. Recently I wanted to switch to kernel-2.6.14-2, because of new
> hardware.
> 
> 2.6.14 requires to use new "yaird" instead of "mkinitrd". Yaird produces
> initrd which can be loaded only by grub-net. In grub-net package I found
> example (see below) for dhcp3 server in
> /usr/share/doc/grub-net/examples/dhcpd.conf.
> 
> There is now example for dnsmasq. I find nothing in documentaion/FAQ. Is
> there any way to add support for grub-net in dnsmasq?
> 
> This is an example for dhcp3 server which I found in grub-net package:
> 
> # Example dhcp3 fragment
> 
> # GRUB (Grand Unified Boot Loader)
> option grub-configfile  code 150 = text;
> 
> class "grub-hosts" {
>         match pick-first-value (option dhcp-client-identifier, hardware);
> 
>         server-name                     "bootserver.example.com";
>         next-server                     192.168.102.252;        # IP of
> TFTP server (only needed if separate from DHCP server)
> #       option tftp-server-name         "192.168.102.252";      # same
> as (or similar to) next-server above (not tested)
>         option                          dhcp-max-message-size 2048;
>         option grub-configfile          "(nd)/grub-menu.lst";
> 
>         if substring (option vendor-class-identifier, 0, 9) = "PXEClient" {
>                 filename        "pxegrub-via-rhine";
>         } else {
>                 filename        "nbgrub-via-rhine";
>         }
> }
> 

It looks like you just need a set of dhcp options to pass information to 
the booting client. It's possible to do that with dnsmasq.

A rough equivalent of the above looks like this (not tested, may have typos)

dhcp-option=150,"(nd)/grub-menu.lst"

# set pxe tag for a PXE client
dhcp-vendorclass=pxe,PXEClient

# boot info for PXE
dhcp-boot=net:pxe,pxegrub-via-rhine,bootserver.example.com,192.168.102.252

# boot info for not PXE
dhcp-boot=nbgrub-via-rhine,bootserver.example.com,192.168.102.252

The only thing this doesn't cover is increasing the DHCP max message 
size: there's no support for that in dnsmasq, but the those options will 
easily fit in a default sized message.

HTH

Simon.