[arch-releng] Make archiso PXE & NBD friendly (server and client mode)

[Gerardo Exequiel Pozzi]

Hello

I recently done some changes for archiso, to make it booteable via PXE 
(Preboot eXecution Environment) and using NBD (Network Block Device). 
Also a minimal server script can be launched to act as server ;)

If booted from network, there is a [nbd] hook, (based on [net]), that 
configures an IP address, then setup a /dev/nbd0 (via nbd-client). (and 
/dev/archiso will point to this device), all the rest is done by current 
archiso hook :) (copytoram option can be used)
If booted normally, [nbd] hook does nothing. Inside the /root, there is 
a simple script that launches dnsmasq enabling tftp and dhcp server, 
finally start the nbd-server that serve the iso file via network.

Tested on real machine, kvm and Virtualbox, works very nice.

Relevant commit (adding nbd hook to pxe_nbd branch ) [#1] and sample 
usage (diff based on my avr-toolchain branch) [#2] All step to make iso 
are here [#3]

NOTE: nbd [#4] package from AUR is needed, so additional steps should be 
done than normal process. :(

Just for fun, all comments welcomed.

Good luck!

[#1] 
http://github.com/djgera/archiso/commit/6023d6f78e3e68c2ad9ae595879a53b677185147
[#2] 
http://github.com/djgera/archiso/commit/ed15360b828671fb6732f8f52ff00de09b2e0419
[#3] 
http://github.com/djgera/archiso/blob/037d265360c76275be0745d77e2f008137550f91/configs/avr-toolchain/README
[#4] http://aur.archlinux.org/packages.php?ID=9691

-- 
Gerardo Exequiel Pozzi ( djgera )
http://www.djgera.com.ar
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