FAI How to build a i386 and x86 64 compatible FAI server on Debian Etch x86 64

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These procedures had been validated on Debian Etch with FAI 3.1.8, and have been revalidated (and updated) for Lenny and FAI 3.2.16.

I was installing an installserver for my company and looking for a way to build and i386 NFSROOT on a amd64 Etch and then build arch specific FAI mirrors and CD images. Here's how I did it.

Important note: this only works if your server runs a amd64 kernel and also only works with amd64 and i386. The reason is simply, because debootstrap installs the packages and then runs the postinst scripts, which in turn (sometimes) run arch-specific binaries, so this only works on amd64, because its possible to execute i386 binaries on amd64. If you want to serve other architecture combinations, you need to create the nfsroot on the target architecture and then copy it to your nfsserver, which can run any OS on any cpu-archtiture :-)

FAI Configuration tuning

All of the processes described below relies on tuning the FAI configuration space. Normally, FAI configuration can be found under an unique directory /etc/fai. To make FAI work with multi architecture, you have to duplicate the configuration space for every architecture. Here is an exemple of such an FAI setup :


To be precise, the directories don't have to be entirely duplicated, only the make-fai-nfsroot.conf file must. Links can be used for the other files or directories under the /etc/fai tree, although apt/sources.list must be a hard link or copy; a soft link will not work.

Cross-Architecture NFSROOT

Create Arch Specific FAI Configuration Direcories

These are the directories that will be used for FAI in this setup. /etc/fai is still there, since several of the files do not change, but shouldn't actually be used directly.

  for dir in /etc/fai-i386 /etc/fai-amd64
	mkdir $dir
	cd $dir
	ln /etc/fai/fai.conf
	ln /etc/fai/NFSROOT
        mkdir $dir/apt
	ln /etc/fai/apt/sources.list apt/
	ln /etc/fai/menu.lst
	cp /etc/fai/make-fai-nfsroot.conf .

Note that you need to either use hard links or make file copies: soft links will not work, because they'll be copied as such to the clients and have no referents.

Make Per-Arch make-fai-nfsroot.conf

Add --arch i386 or --arch amd64 to FAI_DEBOOTSTRAP_OPTS.

Set NFSROOT to /srv/fai/nfsroot-i386 or /srv/fai/nfsroot-amd64, as appropriate.

Set APT_CONFIG to /etc/fai-i386/apt_arch.conf or /etc/fai-amd64/apt_arch.conf, as appropriate.

Build The Per-Arch NFSROOT


  • fai-setup -C /etc/fai-i386 -v
  • fai-setup -C /etc/fai-amd64 -v

You can also run make-fai-nfsroot instead of fai-setup; it's potentially less thorough, but should work.

Configure Network Installation

Run (something like) one of these, depending on what kind of host you are imaging:

  • fai-chboot -k "initrd=$(ls -rt /srv/tftp/fai/initrd.img*i386* | tail -1 | sed 's;.*/;;') root=/dev/nfs nfsroot=$(host $(uname -n) | grep 'has address' | awk '{ print $4 }' | head -1):/srv/fai/nfsroot boot=live ip=dhcp FAI_FLAGS=verbose,sshd,createvt FAI_ACTION=install nfsroot=/srv/fai/nfsroot-i386" $(ls -rt /srv/tftp/fai/vmlinuz*i386* | tail -1 | sed 's;.*/;;') HOST
  • fai-chboot -k "initrd=$(ls -rt /srv/tftp/fai/initrd.img*amd64* | tail -1 | sed 's;.*/;;') root=/dev/nfs nfsroot=$(host $(uname -n) | grep 'has address' | awk '{ print $4 }' | head -1):/srv/fai/nfsroot boot=live ip=dhcp FAI_FLAGS=verbose,sshd,createvt FAI_ACTION=install nfsroot=/srv/fai/nfsroot-amd64" $(ls -rt /srv/tftp/fai/vmlinuz*amd64* | tail -1 | sed 's;.*/;;') HOST

Per-Architecture FAI Mirrors

Here's how to make fai partial Debian mirrors for both architectures.

We need to tell apt-get and frineds what's goin on, so we make a apt_arch.conf file inside /etc/fai-i386 and /etc/fai-amd64.

Simply add thoses lines to /etc/fai-i386/apt_arch.conf ( for /etc/fai-amd64/apt_arch.conf, replace i386 by amd64)

  APT {
	Architecture "i386";

This relies on the NFSROOT changes described above.

for arch in i386 amd64 ; do	    
    export FAI_ETC_DIR=/etc/fai-$arch
    export APT_CONFIG=/etc/fai-$arch/apt_arch.conf
    apt-get update
    fai-mirror -v /srv/fai/mirror-$arch

    export -n APT_CONFIG
    apt-get update

P.S.: Have a look at the option -a of fai-mirror.