This document will describe how to get a rudimentary Live CD built on your own system from a working/running FreeBSD install.
To begin, start by building world and the proper kernel for your live CD. You can build a live CD on a 64-bit box for 32-bit fairly easily. The process is described briefly here.
Building world and kernel for a live CD is no different than building it for a running system. During the install process, we want to specify a new location, which will be our live CD. You do this with the DESTDIR variable, given to make.
# cd /usr/src # make buildworld DESTDIR=/path/to/livecd # make installworld DESTDIR=/path/to/livecd # make buildkernel DESTDIR=/path/to/livecd # make installkernel DESTDIR=/path/to/livecd # make distribution DESTDIR=/path/to/livecd
If you're building a 64-bit live CD on a 32-bit box, or something else, add TARGET_ARCH and TARGET variables to your build/install. Here's an example of a 32-bit build being done on a 64-bit system:
# make buildworld TARGET_ARCH=i386 TARGET=i386 DESTDIR=/path/to/livecd # make installworld TARGET_ARCH=i386 TARGET=i386 DESTDIR=/path/to/livecd # make buildkernel TARGET_ARCH=i386 TARGET=i386 DESTDIR=/path/to/livecd # make installkernel TARGET_ARCH=i386 TARGET=i386 DESTDIR=/path/to/livecd # make distribution TARGET_ARCH=i368 TARGET=i386 DESTDIR=/path/to/livecd
Configuration / Installing Packages
Once these operations are complete, you will have a 'working' system in /path/to/livecd (make sure the directory exists before putting files there!) Now, you can chroot to this directory and install a ports tree, add packages, etc. Again, if you're building a 32-bit live CD on a 64-bit system, or something similar, you need to do a couple things first.
Setup a working devfs in your chroot:
# mount -t devfs devfs /path/to/livecd/dev # chroot /path/to/livecd
As above, if you're cross-compiling, you need to set a couple environment variables. Once inside your chroot, set the following environment variables:
MACHINE i386 UNAME_p i386 UNAME_m i386
You should now be able to pkg_add or build any ports you need for your live CD. In our example, we're using this live CD to restore backups via rsync from a remote server.
The following tasks were completed for our example:
- Install rsync (pkg_add -rv rsync)
- run /etc/rc.d/sshd onestart to create ssh host keys (so they're static on our live cd)
- set a password for the root user
- enabled root ssh in sshd_config
- added a script to /usr/local/etc/rc.d/ to search for and run dhclient on all interfaces
- create a memory disk and union mount it over /etc so resolv.conf can be written by dhclient.
- create a file /etc/issue if you want a banner displayed prior to login.
/dev/acd0 / cd9660 ro 0 0 md /mnt/etc mfs rw,-s32m,-S 2 0 md /mnt/root mfs rw,-s32m,-S 2 0 /mnt/etc /etc unionfs rw 0 0 /mnt/root /root unionfs rw 0 0
#!/bin/sh echo "Configuring network interfaces for DHCP..." echo "" #ifconfig | grep flags | cut -f 1 -d : | grep -vE 'carp|lo|bridge|tun|tap' | xargs -D 1 -I III dhclient III rawint=`ifconfig | grep flags | cut -f 1 -d : | grep -vE 'carp|lo|bridge|tun|tap'` for int in $rawint do if [ ! `ifconfig $int | grep "no carrier"` ]; then dhclient $int fi done
## LiveCD Options update_motd="NO" syslogd_enable="NO" sendmail_enable="NONE" cleanvar_enable="NO" hostid_enable="NO" ip6addrctl_enable="NO" moused_nondefault_enable="NO" sendmail_submit_enable="NO" sendmail_outbound_enable="NO" sendmail_msp_queue_enable="NO" cron_enable="NO" crashinfo_enable="NO" virecover_enable="NO" newsyslog_enable="NO" mixer_enable="NO" root_rw_mount="NO" hostname="CLX_LIVECD" ## LiveCD Daemons sshd_enable="YES"
Once the image is built, we create an ISO using mkisofs, which can be had from /usr/ports/sysutils/cdrtools. The following command will create an ISO with the proper options:
# mkisofs -no-emul-boot -R -b boot/cdboot -J -publisher "ClaimLynx, Inc." -V FreeBSD-LiveCD -o ~/clx2.iso path/to/dir/
I test my ISOs using VirtualBox. You're also welcome to burn them to a CD-R/W and try booting from it.
If you need a smaller ISO than the one we have here (about 440MB), you can remove the following things from your /path/to/livecd:
- Josh Paetzel (most of this article)