make_live_iso

Introduction

This repo builds a Docker image that can then be used to create a bootable Ubuntu Live ISO file.

I've based this on the instructions at https://github.com/mvallim/live-custom-ubuntu-from-scratch

You can use this as it stands to build a basic installable (with the Xfce desktop) or you can customise to add additional packages (such as a browser) to meet specific needs.

Prerequisites

• An OS/X or Linux (not yet tested) desktop, or compatible shell.
• Docker (I have desktop 2.1.0.4, engine 19.03.4)
• About 30G of free disk

A virtualisation application such as VirtualBox is useful for testing

To boot on an actual machine, you can write a USB or SD card, or if you have retro hardware, a DVD.

Usage (from repo)

Ensure you have Docker running (and no other Docker containers active (fixme))

Clone this repo: git clone https://github.com/richdrich/make_live_iso.git and cd to it cd make_live_iso

Build the image (takes a while): ./docker_build_image

Generate the iso builder/generate_iso

The ISO file will be in 'out/live_stick.iso'.

To write this to a USB stick or SD card, Balena Etcher is recommended.

If you have an issue in the build and a Docker container is left running, ./docker_rm will fix.

ssh access

If you want to configure your booted OS for ssh access (e.g. for development) then setting SSH_PUB_KEY to your public key path before running generate_iso will do this. This copies the public key into the ~ubuntu/.ssh/authorized_keys which grants an SSH user access. You can then configure your ssh client to use the corresponding private key and log in as ubuntu. You may also want StrictHostKeyChecking no as the host id will change every time you build.

• NOTE: this will authorize access to every system booted from the ISO and is of limited use for 'production' *

Customization

You can customise the ISO by extending the make_live_iso image.

• Create a Dockerfile in your own directory with:

FROM make_live_iso

The install process uses three customisation files:

chroot_custom runs as chroot (e.g. as if it was in the booted system) and installs any packages you require.

It looks like:

#!/bin/bash -x

echo "chroot_custom"

mount none -t proc /proc
mount none -t sysfs /sys
mount none -t devpts /dev/pts
export HOME=/root
export LC_ALL=C

echo "APT::Acquire::Retries \"3\";" > /etc/apt/apt.conf.d/80-retries

[ INSTALL, ETC ]

apt-get clean
rm -rf /tmp/* ~/.bash_history
umount /proc
umount /sys
umount /dev/pts
export HISTSIZE=0

echo "chroot_custom"

Use a stanza like:

ADD chroot_custom /live-ubuntu-from-scratch/chroot_custom
RUN chmod a+x /live-ubuntu-from-scratch/chroot/chroot_custom

in your Dockerfile to install this.

pre_custom runs outside chroot and can be used to build any required custom code, etc

Install with e.g:

ADD pre_custom /root
RUN chmod a+x /root/pre_custom

post_custom runs after and outside the chroot and can be used for any other customisation commands.