Tool used to create the raspberrypi.org Raspbian images
pi-gen runs on Debian based operating systems. Currently it is only supported on either Debian Stretch or Ubuntu Xenial and is known to have issues building on earlier releases of these systems.
To install the required dependencies for pi-gen you should run:
apt-get install quilt parted realpath qemu-user-static debootstrap zerofree pxz zip \ dosfstools bsdtar libcap2-bin grep rsync xz-utils
depends contains a list of tools needed. The format of this
build.sh will source the file
config in the current
working directory. This bash shell fragment is intended to set needed
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=Raspbianis 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
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-cacheror 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
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.
Directory in which
pi-genbuilds 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_DIRstores 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.
Output directory for target system images and NOOBS bundles.
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.
A simple example for building Raspbian:
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.shwhich 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 -yparameters 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.
vi config # Edit your config file. See above. ./build-docker.sh
If everything goes well, your finished image will be in the
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:
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
There is a possibility that even when running from a docker container, the
qemu-user-static will silently fail when building the image
binfmt-support must be enabled on the underlying kernel. An easy
fix is to ensure
binfmt-support is installed on the host machine before
./build-docker.sh script (or using your own docker build
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-bootloaderwhich 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-essentialpackage. 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 - Raspbian 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 official Raspbian Desktop image. Right now only adds Mathematica.
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
directories you wish not to include.
Then add an empty file named
./stage4 (if building up to stage 2) or
./stage2 (if building a minimal system).
# Example for building a lite system echo "IMG_NAME='Raspbian'" > config touch ./stage3/SKIP ./stage4/SKIP ./stage5/SKIP touch ./stage4/SKIP_IMAGES ./stage5/SKIP_IMAGES sudo ./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
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