Tool used to create the raspberrypi.org Raspbian images
Dependencies
pi-gen runs on Debian based operating systems. Currently it is only
supported on either Debian Buster or Ubuntu Xenial and is known to have
issues building on earlier releases of these systems. On other Linux
distributions it may be possible to use the Docker build described
below.
To install the required dependencies for pi-gen you should run:
The file depends contains a list of tools needed. The
format of this package is
<tool>[:<debian-package>].
Config
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.
If you have Docker installed, you can set up a local apt caching
proxy to like speed up subsequent builds like this:
docker-compose up -d
echo 'APT_PROXY=http://172.17.0.1:3142' >> config
BASE_DIR (Default: location of
build.sh)
CAUTION: Currently, changing this value will
probably break build.sh
Top-level directory for pi-gen. Contains stage
directories, build scripts, and by default both work and deployment
directories.
WORK_DIR (Default:
"$BASE_DIR/work")
Directory in which pi-gen builds the target system. This
value can be changed if you have a suitably large, fast storage location
for stages to be built and cached. Note, WORK_DIR stores a
complete copy of the target system for each build stage, amounting to
tens of gigabytes in the case of Raspbian.
CAUTION: If your working directory is on an NTFS
partition you probably won't be able to build. Make sure this is a
proper Linux filesystem.
DEPLOY_DIR (Default:
"$BASE_DIR/deploy")
Output directory for target system images and NOOBS bundles.
DEPLOY_ZIP (Default: 1)
Setting to 0 will deploy the actual image
(.img) instead of a zipped image
(.zip).
USE_QEMU (Default: "0")
Setting to '1' enables the QEMU mode - creating an image that can be
mounted via QEMU for an emulated environment. These images include
"-qemu" in the image file name.
LOCALE_DEFAULT (Default: "en_GB.UTF-8" )
Default system locale.
HOSTNAME (Default: "raspberrypi" )
Setting the hostname to the specified value.
KEYBOARD_KEYMAP (Default: "gb" )
Default keyboard keymap.
To get the current value from a running system, run
debconf-show keyboard-configuration and look at the
keyboard-configuration/xkb-keymap value.
KEYBOARD_LAYOUT (Default: "English (UK)" )
Default keyboard layout.
To get the current value from a running system, run
debconf-show keyboard-configuration and look at the
keyboard-configuration/variant value.
TIMEZONE_DEFAULT (Default: "Europe/London" )
Default keyboard layout.
To get the current value from a running system, look in
/etc/timezone.
FIRST_USER_NAME (Default: "pi" )
Username for the first user
FIRST_USER_PASS (Default: "raspberry")
Password for the first user
WPA_ESSID, WPA_PASSWORD and
WPA_COUNTRY (Default: unset)
If these are set, they are use to configure
wpa_supplicant.conf, so that the raspberry pi can
automatically connect to a wifi network on first boot. If
WPA_ESSID is set and WPA_PASSWORD is unset an
unprotected wifi network will be configured.
ENABLE_SSH (Default: 0)
Setting to 1 will enable ssh server for remote log in.
Note that if you are using a common password such as the defaults there
is a high risk of attackers taking over you RaspberryPi.
STAGE_LIST (Default: stage*)
If set, then instead of working through the numeric stages in order,
this list will be followed. For example setting to
"stage0 stage1 mystage stage2" will run the contents of
mystage before stage2. Note that quotes are needed around
the list. An absolute or relative path can be given for stages outside
the pi-gen directory.
A simple example for building Raspbian:
IMG_NAME='Raspbian'
The config file can also be specified on the command line as an
argument the build.sh or build-docker.sh
scripts.
./build.sh -c myconfig
This is parsed after config so can be used to override
values set there.
How the build process works
The following process is followed to build images:
Loop through all of the stage directories in alphanumeric
order
Move on to the next directory if this stage directory contains a
file called "SKIP"
Run the script prerun.sh which is generally just
used to copy the build directory between stages.
In each stage directory loop through each subdirectory and then
run each of the install scripts it contains, again in alphanumeric
order. These need to be named with a two digit padded number at the
beginning. There are a number of different files and directories which
can be used to control different parts of the build process:
00-run.sh - A unix shell script. Needs to be
made executable for it to run.
00-run-chroot.sh - A unix shell script which
will be run in the chroot of the image build directory. Needs to be made
executable for it to run.
00-debconf - Contents of this file are passed to
debconf-set-selections to configure things like locale, etc.
00-packages - A list of packages to install. Can
have more than one, space separated, per line.
00-packages-nr - As 00-packages, except these
will be installed using the --no-install-recommends -y
parameters to apt-get.
00-patches - A directory containing patch files
to be applied, using quilt. If a file named 'EDIT' is present in the
directory, the build process will be interrupted with a bash session,
allowing an opportunity to create/revise the patches.
If the stage directory contains files called "EXPORT_NOOBS" or
"EXPORT_IMAGE" then add this stage to a list of images to
generate
Generate the images for any stages that have specified
them
It is recommended to examine build.sh for finer details.
Docker Build
Docker can be used to perform the build inside a container. This
partially isolates the build from the host system, and allows using the
script on non-debian based systems (e.g. Fedora Linux). The isolate is
not complete due to the need to use some kernel level services for arm
emulation (binfmt) and loop devices (losetup).
To build:
vi config # Edit your config file. See above../build-docker.sh
If everything goes well, your finished image will be in the
deploy/ folder. You can then remove the build container
with docker rm -v pigen_work
If something breaks along the line, you can edit the corresponding
scripts, and continue:
CONTINUE=1 ./build-docker.sh
To examine the container after a failure you can enter a shell within
it using:
sudo docker run -it--privileged--volumes-from=pigen_work pi-gen /bin/bash
After successful build, the build container is by default removed.
This may be undesired when making incremental changes to a customized
build. To prevent the build script from remove the container add
PRESERVE_CONTAINER=1 ./build-docker.sh
There is a possibility that even when running from a docker
container, the installation of qemu-user-static will
silently fail when building the image because
binfmt-supportmust be enabled on the underlying
kernel. An easy fix is to ensure binfmt-support is
installed on the host machine before starting the
./build-docker.sh script (or using your own docker build
solution).
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 - Normal Raspbian image. System meant to
fit on a 4GB card. More development tools, an email client, learning
tools like Scratch, specialized packages like sonic-pi, system
documentation, office productivity, etc. This is the stage that installs
all of the things that make Raspbian friendly to new users.
Stage 5 - The Raspbian Full image.
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 add an empty file named SKIP_IMAGES to
./stage4 and ./stage5 (if building up to stage
2) or to ./stage2 (if building a minimal system).
# Example for building a lite systemecho"IMG_NAME='Raspbian'"> configtouch ./stage3/SKIP ./stage4/SKIP ./stage5/SKIPtouch ./stage4/SKIP_IMAGES ./stage5/SKIP_IMAGESsudo ./build.sh # or ./build-docker.sh
If you wish to build further configurations upon (for example) the
lite system, you can also delete the contents of ./stage3
and ./stage4 and replace with your own contents in the same
format.
Skipping stages to
speed up development
If you're working on a specific stage the recommended development
process is as follows:
Add a file called SKIP_IMAGES into the directories containing
EXPORT_* files (currently stage2, stage4 and stage5)
Add SKIP files to the stages you don't want to build. For example,
if you're basing your image on the lite image you would add these to
stages 3, 4 and 5.
Run build.sh to build all stages
Add SKIP files to the earlier successfully built stages
Modify the last stage
Rebuild just the last stage using
sudo CLEAN=1 ./build.sh
Once you're happy with the image you can remove the SKIP_IMAGES
files and export your image to test
Linux is able execute binaries from other architectures, meaning that
it should be possible to make use of pi-gen on an x86_64
system, even though it will be running ARM binaries. This requires
support from the binfmt_misc
kernel module.
You may see the following error:
update-binfmts: warning: Couldn't load the binfmt_misc module.
To resolve this, ensure that the following files are available
(install them if necessary):
