Upon execution, build.sh will source the file
config in the current working directory. This bash shell
fragment is intended to set needed environment variables.
The following environment variables are supported:
IMG_NAMErequired (Default:
unset)
The name of the image to build with the current stage directories.
Setting IMG_NAME=Raspbian is logical for an unmodified
RPi-Distro/pi-gen build, but you should use something else for a
customized version. Export files in stages may add suffixes to
IMG_NAME.
APT_PROXY (Default: unset)
If you require the use of an apt proxy, set it here. This proxy
setting will not be included in the image, making it safe to use an
apt-cacher or similar package for development.
A simple example for building Raspbian:
IMG_NAME='Raspbian'
Stage Anatomy
Raspbian Stage Overview
The build of Raspbian is divided up into several stages for logical
clarity and modularity. This causes some initial complexity, but it
simplifies maintenance and allows for more easy customization.
Stage 0 - bootstrap. The primary purpose of this
stage is to create a usable filesystem. This is accomplished largely
through the use of debootstrap, which creates a minimal
filesystem suitable for use as a base.tgz on Debian systems. This stage
also configures apt settings and installs
raspberrypi-bootloader which is missed by debootstrap. The
minimal core is installed but not configured, and the system will not
quite boot yet.
Stage 1 - truly minimal system. This stage makes
the system bootable by installing system files like
/etc/fstab, configures the bootloader, makes the network
operable, and installs packages like raspi-config. At this stage the
system should boot to a local console from which you have the means to
perform basic tasks needed to configure and install the system. This is
as minimal as a system can possibly get, and its arguably not really
usable yet in a traditional sense yet. Still, if you want minimal, this
is minimal and the rest you could reasonably do yourself as
sysadmin.
Stage 2 - lite system. This stage produces the
Raspbian-Lite image. It installs some optimized memory functions, sets
timezone and charmap defaults, installs fake-hwclock and ntp, wifi and
bluetooth support, dphys-swapfile, and other basics for managing the
hardware. It also creates necessary groups and gives the pi user access
to sudo and the standard console hardware permission groups.
There are a few tools that may not make a whole lot of sense here for
development purposes on a minimal system such as basic python and lua
packages as well as the build-essential package. They are
lumped right in with more essential packages presently, though they need
not be with pi-gen. These are understandable for Raspbian's target
audience, but if you were looking for something between truly minimal
and Raspbian-lite, here's where you start trimming.
Stage 3 - desktop system. Here's where you get
the full desktop system with X11 and LXDE, web browsers, git for
development, Raspbian custom UI enhancements, etc. This is a base
desktop system, with some development tools installed.
Stage 4 - complete Raspbian system. More
development tools, an email client, learning tools like Scratch,
specialized packages like sonic-pi and wolfram-engine, system
documentation, office productivity, etc. This is the stage that installs
all of the things that make Raspbian friendly to new users.
Stage specification
If you wish to build up to a specified stage (such as building up to
stage 2 for a lite system), place an empty file named SKIP
in each of the ./stage directories you wish not to
include.
Then remove the EXPORT* files from ./stage4
(if building up to stage 2) or from ./stage2 (if building a
minimal system).
# Example for building a lite system
$ touch ./stage3/SKIP ./stage4/SKIP
$ rm stage4/EXPORT*
