How to roll your own Debian based Linux distro

Mikael Ståldal

Goal

To build a minimal Debian based Linux system with a fully functional bash shell, TCP/IP networking with DHCP client and apt setup to be able to install any package from the Debian repositories. The resulting system will use about 157 MB disk space and consume less than 10 MB RAM.

This is now implemented in Bachata Linux.

Prerequisites

A Debian based Linux system to work from (e.g. Ubuntu desktop) with the debootstrap and extlinux packages installed. Some virtualization environment is highly recommended for testing, such as KVM/QEMU.

Install system

This will install the system on a disk mounted at mnt. Choose a hostname for the instance to create, substitute it for ${HOSTNAME}. Substitute the URL to your nearest Debian mirror for ${MIRROR}.

  1. sudo debootstrap --variant=minbase --include=localepurge,netbase,ifupdown,net-tools,isc-dhcp-client,linux-base,linux-image-2.6-686,linux-image-2.6.32-5-686 squeeze mnt ${MIRROR}
  2. sudo rm mnt/etc/udev/rules.d/70-persistent-net.rules
  3. sudo rm mnt/var/cache/apt/archives/*
  4. sudo rm mnt/var/cache/apt/*.bin
  5. sudo rm mnt/var/lib/apt/lists/*
  6. sudo rm mnt/var/log/dpkg.log*
  7. sudo rm mnt/var/log/apt/*
  8. sudo mkdir mnt/boot/extlinux
  9. sudo extlinux --install mnt/boot/extlinux
  10. sudoedit mnt/boot/extlinux/syslinux.cfg
default linux

    label linux
    kernel /boot/vmlinuz-2.6.32-5-686
    append initrd=/boot/initrd.img-2.6.32-5-686 root=UUID=${UUID} ro quiet
_Only for KVM/QEMU:_ add `console=ttyS0` to the “append” line
  1. sudoedit mnt/etc/inittab
    For KVM/QEMU: uncomment getty ttyS0 and comment out getty tty[1-6]
    For others: comment out getty tty[2-6]
  2. sudoedit mnt/etc/passwd – blank password for root
  3. sudoedit mnt/etc/network/interfaces
auto lo
iface lo inet loopback
allow-hotplug eth0
iface eth0 inet dhcp
  1. sudoedit mnt/etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>             <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid   0       0
UUID=${UUID}        /               ext2    errors=remount-ro     0       1
  1. sudoedit mnt/etc/hostname
${HOSTNAME}
  1. sudoedit mnt/etc/locale.nopurge
MANDELETE

DONTBOTHERNEWLOCALE

SHOWFREEDSPACE

#QUICKNDIRTYCALC

#VERBOSE

en
  1. sudoedit mnt/etc/apt/sources.list
deb ${MIRROR} squeeze main
deb-src ${MIRROR} squeeze main

deb http://security.debian.org/ squeeze/updates main
deb-src http://security.debian.org/ squeeze/updates main

# squeeze-updates, previously known as 'volatile'
deb ${MIRROR} squeeze-updates main
deb-src ${MIRROR} squeeze-updates main
  1. sudoedit mnt/etc/apt/apt.conf.d/02nocache
Dir::Cache {
  srcpkgcache "";
  pkgcache "";
}
  1. sudoedit mnt/etc/apt/apt.conf.d/02compress-indexes
Acquire::GzipIndexes "true";
Acquire::CompressionTypes::Order:: "gz";
  1. sudo chroot mnt localepurge
  2. sudo chroot mnt apt-get update
  3. sudo chroot mnt passwd root

Install on a physical disk

  1. Create a bootable partition of at least 288 MB with system code 83 “Linux” using fdisk
  2. sudo mke2fs -L ${HOSTNAME} -t ext2 /dev/xxxx
  3. sudo UUID=`blkid -o value -s UUID /dev/xxxx`
  4. mkdir mnt
  5. sudo mount /dev/xxxx mnt
  6. Install system as above
  7. sudo umount mnt

Install in KVM/QEMU

  1. dd if=/dev/zero of=${HOSTNAME}.img bs=1024 count=288K
  2. mke2fs -L ${HOSTNAME} -t ext2 ${HOSTNAME}.img
  3. UUID=`blkid -o value -s UUID ${HOSTNAME}.img`
  4. mkdir mnt
  5. sudo mount ${HOSTNAME}.img mnt
  6. Install system as above
  7. sudo umount mnt
  8. virt-install --connect qemu:///system -n ${HOSTNAME} -r 256 --os-type linux --os-variant debiansqueeze --import --disk path=${HOSTNAME}.img --network=network:default --graphics none --virt-type kvm

Use --virt-type qemu if your CPU doesn’t support virtualization.

Then you can start it with virsh start ${HOSTNAME} and connect to it with virsh console ${HOSTNAME}

For some reason, doing reboot from inside the guest doesn’t seem to work properly. virsh reboot and virsh shutdown doesn’t work either (you might get that to work by installing some ACPI stuff in the guest). Use halt from inside the guest to have a clean shutdown, and then restart it with virsh start.

Install in VirtualBox 4.1

First create a virtual machine in VirtualBox with an empty VDI disk ${VDI_FILE} of least 288 MB.

Install VDI mounting tool according to this description.

  1. mkdir vdi-mount
  2. vdfuse-v82a -f ${VDI_FILE} vdi-mount
  3. mke2fs -L ${HOSTNAME} -t ext2 vdi-mount/EntireDisk
  4. mkdir mnt
  5. sudo mount vdi-mount/EntireDisk mnt
  6. Install system as above
  7. sudo umount mnt
  8. fusermount -u vdi-mount

Then start the virtual machine in VirtualBox.

Install in other virtualization environments

Please tell me how!