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https://github.com/RPi-Distro/pi-gen

Tool used to create the official Raspberry Pi OS images
https://github.com/RPi-Distro/pi-gen

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Tool used to create the official Raspberry Pi OS images

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# pi-gen



Tool used to create Raspberry Pi OS images, and custom images based on Raspberry Pi OS,

which was in turn derived from the Raspbian project.



**Note**: Raspberry Pi OS 32 bit images are based primarily on Raspbian, while

Raspberry Pi OS 64 bit images are based primarily on Debian.



## Dependencies



pi-gen runs on Debian-based operating systems released after 2017, and we

always advise you use the latest OS for security reasons.



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:



```bash

apt-get install coreutils quilt parted qemu-user-static debootstrap zerofree zip \

dosfstools libarchive-tools libcap2-bin grep rsync xz-utils file git curl bc \

gpg pigz xxd

```



The file `depends` contains a list of tools needed.  The format of this

package is `[:]`.



## Getting started with building your images



Getting started is as simple as cloning this repository on your build machine. You

can do so with:



```bash

git clone https://github.com/RPI-Distro/pi-gen.git

```



`--depth 1` can be added afer `git clone` to create a shallow clone, only containing

the latest revision of the repository. Do not do this on your development machine.



Also, be careful to clone the repository to a base path **NOT** containing spaces.

This configuration is not supported by debootstrap and will lead to `pi-gen` not

running.



After cloning the repository, you can move to the next step and start configuring

your build.



## 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_NAME` **required** (Default: unset)



   The name of the image to build with the current stage directories. Use this

   variable to set the root name of your OS, eg `IMG_NAME=Frobulator`.

   Export files in stages may add suffixes to `IMG_NAME`.



 * `PI_GEN_RELEASE` (Default: `Raspberry Pi reference`)



   The release name to use in `/etc/issue.txt`. The default should only be used

   for official Raspberry Pi builds.



* `RELEASE` (Default: bookworm)



   The release version to build images against. Valid values are any supported

   Debian release. However, since different releases will have different sets of

   packages available, you'll need to either modify your stages accordingly, or

   checkout the appropriate branch. For example, if you'd like to build a

   `bullseye` image, you should do so from the `bullseye` branch.



 * `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.



 * `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_COMPRESSION` (Default: `zip`)



   Set to:

   * `none` to deploy the actual image (`.img`).

   * `zip` to deploy a zipped image (`.zip`).

   * `gz` to deploy a gzipped image (`.img.gz`).

   * `xz` to deploy a xzipped image (`.img.xz`).



 * `DEPLOY_ZIP` (Deprecated)



   This option has been deprecated in favor of `DEPLOY_COMPRESSION`.



   If `DEPLOY_ZIP=0` is still present in your config file, the behavior is the

   same as with `DEPLOY_COMPRESSION=none`.



 * `COMPRESSION_LEVEL` (Default: `6`)



   Compression level to be used when using `zip`, `gz` or `xz` for

   `DEPLOY_COMPRESSION`. From 0 to 9 (refer to the tool man page for more

   information on this. Usually 0 is no compression but very fast, up to 9 with

   the best compression but very slow ).



 * `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.



 * `TARGET_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. This user only exists during the image creation process. Unless

   `DISABLE_FIRST_BOOT_USER_RENAME` is set to `1`, this user will be renamed on the first boot with

   a name chosen by the final user. This security feature is designed to prevent shipping images

   with a default username and help prevent malicious actors from taking over your devices.



 * `FIRST_USER_PASS` (Default: unset)



   Password for the first user. If unset, the account is locked.



 * `DISABLE_FIRST_BOOT_USER_RENAME` (Default: `0`)



   Disable the renaming of the first user during the first boot. This make it so `FIRST_USER_NAME`

   stays activated. `FIRST_USER_PASS` must be set for this to work. Please be aware of the implied

   security risk of defining a default username and password for your devices.



 * `WPA_COUNTRY` (Default: unset)



   Sets the default WLAN regulatory domain and unblocks WLAN interfaces. This should be a 2-letter ISO/IEC 3166 country Code, i.e. `GB`



 * `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 Raspberry Pi.



  * `PUBKEY_SSH_FIRST_USER` (Default: unset)



   Setting this to a value will make that value the contents of the FIRST_USER_NAME's ~/.ssh/authorized_keys.  Obviously the value should

   therefore be a valid authorized_keys file.  Note that this does not

   automatically enable SSH.



  * `PUBKEY_ONLY_SSH` (Default: `0`)



   * Setting to `1` will disable password authentication for SSH and enable

   public key authentication.  Note that if SSH is not enabled this will take

   effect when SSH becomes enabled.



 * `SETFCAP` (Default: unset)



   * Setting to `1` will prevent pi-gen from dropping the "capabilities"

   feature. Generating the root filesystem with capabilities enabled and running

   it from a filesystem that does not support capabilities (like NFS) can cause

   issues. Only enable this if you understand what it is.



 * `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 Raspberry Pi OS:



```bash

IMG_NAME='raspios'

```



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:



 * Interate through all of the stage directories in alphanumeric order



 * Bypass a stage directory if it 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 iterate 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 isolation is not complete due to the need to use

some kernel level services for arm emulation (binfmt) and loop devices (losetup).



To build:



```bash

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 you encounter errors during the build, you can edit the corresponding scripts, and

continue:



```bash

CONTINUE=1 ./build-docker.sh

```



To examine the container after a failure you can enter a shell within it using:



```bash

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



```bash

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-support` _must 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).



### Passing arguments to Docker



When the docker image is run various required command line arguments are provided.  For example the system mounts the `/dev` directory to the `/dev` directory within the docker container.  If other arguments are required they may be specified in the PIGEN_DOCKER_OPTS environment variable.  For example setting `PIGEN_DOCKER_OPTS="--add-host foo:192.168.0.23"` will add '192.168.0.23   foo' to the `/etc/hosts` file in the container.  The `--name`

and `--privileged` options are already set by the script and should not be redefined.



## 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. As a result, this stage will not boot.



 - **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.



 - **Stage 2** - lite system.  This stage produces the Raspberry Pi OS Lite image.

   Stage 2 installs some optimized memory functions, sets timezone and charmap

   defaults, installs fake-hwclock and ntp, wireless LAN 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.



   Note: Raspberry Pi OS Lite contains a number of tools for development,

   including `Python`, `Lua` and the `build-essential` package. If you are

   creating an image to deploy in products, be sure to remove extraneous development

   tools before deployment.



 - **Stage 3** - desktop system.  Here's where you get the full desktop system

   with X11 and LXDE, web browsers, git for development, Raspberry Pi OS custom UI

   enhancements, etc.  This is a base desktop system, with some development

   tools installed.



 - **Stage 4** - Normal Raspberry Pi OS image. System meant to fit on a 4GB card.

   This is the    stage that installs most things that make Raspberry Pi OS friendly

   to new users - e.g. system documentation.



 - **Stage 5** - The Raspberry Pi OS Full image. More development

   tools, an email client, learning tools like Scratch, specialized packages

   like sonic-pi, office productivity, etc.



### 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).



```bash

# Example for building a lite system

echo "IMG_NAME='raspios'" > 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 `./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



# Troubleshooting



## `64 Bit Systems`

Please note there is currently an issue when compiling with a 64 Bit OS. See

https://github.com/RPi-Distro/pi-gen/issues/271



A 64 bit image can be generated from the `arm64` branch in this repository. Just

replace the command from [this section](#getting-started-with-building-your-images)

by the one below, and follow the rest of the documentation:

```bash

git clone --branch arm64 https://github.com/RPI-Distro/pi-gen.git

```



If you want to generate a 64 bits image from a Raspberry Pi running a 32 bits

version, you need to add `arm_64bit=1` to your `config.txt` file and reboot your

machine. This will restart your machine with a 64 bits kernel. This will only

work from a Raspberry Pi with a 64-bit capable processor (i.e. Raspberry Pi Zero

2, Raspberry Pi 3 or Raspberry Pi 4).



## `binfmt_misc`



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`](https://en.wikipedia.org/wiki/Binfmt_misc)

kernel module.



You may see one of the following errors:



```

update-binfmts: warning: Couldn't load the binfmt_misc module.

```

```

W: Failure trying to run: chroot "/pi-gen/work/test/stage0/rootfs" /bin/true

and/or

chroot: failed to run command '/bin/true': Exec format error

```



To resolve this, ensure that the following files are available (install them if necessary):



```

/lib/modules/$(uname -r)/kernel/fs/binfmt_misc.ko

/usr/bin/qemu-arm-static

```



You may also need to load the module by hand - run `modprobe binfmt_misc`.



If you are using WSL to build you may have to enable the service `sudo update-binfmts --enable`