BCCD:Fossilizing

Fossilizing the BCCD

This section outlines the steps required to disassemble a BCCD ISO, manifest it on a hard disk drive, and boot from that hard drive. Most or all of this must be done as root.

Mount the Images

The Basic Images

cd /mnt # or where ever
mkdir bccd
mount -t iso9660 -o loop bccd-ppc-2005-08-30T00-0500.iso bccd

# on PPC
mkdir initrd
gunzip < bccd/boot/root.bin > initrd.ext2
mount -t ext2 -o loop initrd.ext2 initrd

# on x86
mkdir lnx
mount -o loop bccd/lnx.img lnx
mkdir root
gunzip < lnx/root.bin > root.ext2
mount -o loop root.ext2 root

The singularity

First, decompress the singularity with the cloop utility extract_compressed_fs:

wget http://developer.linuxtag.net/knoppix/sources/cloop_0.66-1.tar.gz
tar xzf cloop_0.66-1.tar.gz
cd cloop-0.66
vim Makefile # add APPSONLY=1 at the top
make zcode
make extract_compressed_fs
./extract_compressed_fs ../bccd/singularity > ../singularity.romfs
cd ..

The latest currently-available version of cloop (2.01) doesn't work for this purpose; others might (I didn't experiment), but 0.66 definitely does.

Next, mount the singularity (you must have romfs support compiled into the kernel):

mkdir singularity
mount -t romfs -o loop singularity.romfs singularity

Extract the singularity

cd singularity
tar cf - . | (cd /path/to/destination/partition;tar xvf -)

Create a working initrd

Create an initrd for fossilized booting with the linuxrc at http://ppckernel.org/~tmcnulty/bccd/linuxrc:

cd /mnt/root # or where ever you mounted root.ext2 (from root.bin)
wget http://ppckernel.org/~tmcnulty/bccd/linuxrc # replace the existing linuxrc
chmod a+x linuxrc
cd ..
umount root
gzip < root.ext2 > /path/to/destination/partition/boot/root.bin

Edit singularity-init

Add / remount read-write hook

Edit /sbin/singularity-init to remount / read-write during init, using the following command:

debug "Remounting / read-write..."
mount -o rw,remount /dev/root /

This can be placed somewhere around the proc mount command.

Add network setup to singularity-init

ifconfig eth0 inet 192.168.10.1 netmask 255.255.255.0 broadcast 192.168.10.255 up
route add default gw 192.168.10.1 eth0

Configure the bootloader

Configure your bootloader (e.g., yaboot, lilo, or grub) as follows:

• boot the kernel /boot/vmlinux on PowerPC or /boot/bzImage on x86
• use the initrd /boot/root.bin
• execute the init script /linuxrc.

Here is a sample lilo.conf.

TODO

• fix the mounting commands so that / is only mounted once (?)
• decide how to handle directories like /etc that are mounted in ram at /dev/rw/etc and populated with items from /etc.ro (leave as is, or create a script to simplify the setup for hard disk booting?)
  • Kevin's done this, we just need to document
• modify init scripts to make them appropriate for hard disk booting (e.g., remove the "Enter a password for the default user" prompt)
• finish setting up networking
• create a patch against the original singularity image for /sbin/singularity-init and other modified configuration files for automating the fossilize process
• last but not least, keep track of changes we make!

Good luck! Direct questions and comments to tmcnulty@ppckernel.org.