Burrow Raspberry Pi Image
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  1. # pi-gen
  2. _Tool used to create the raspberrypi.org Raspbian images_
  3. ## Dependencies
  4. pi-gen runs on Debian based operating systems. Currently it is only supported on
  5. either Debian Buster or Ubuntu Xenial and is known to have issues building on
  6. earlier releases of these systems. On other Linux distributions it may be possible
  7. to use the Docker build described below.
  8. To install the required dependencies for pi-gen you should run:
  9. ```bash
  10. apt-get install coreutils quilt parted qemu-user-static debootstrap zerofree zip \
  11. dosfstools bsdtar libcap2-bin grep rsync xz-utils file git curl
  12. ```
  13. The file `depends` contains a list of tools needed. The format of this
  14. package is `<tool>[:<debian-package>]`.
  15. ## Config
  16. Upon execution, `build.sh` will source the file `config` in the current
  17. working directory. This bash shell fragment is intended to set needed
  18. environment variables.
  19. The following environment variables are supported:
  20. * `IMG_NAME` **required** (Default: unset)
  21. The name of the image to build with the current stage directories. Setting
  22. `IMG_NAME=Raspbian` is logical for an unmodified RPi-Distro/pi-gen build,
  23. but you should use something else for a customized version. Export files
  24. in stages may add suffixes to `IMG_NAME`.
  25. * `APT_PROXY` (Default: unset)
  26. If you require the use of an apt proxy, set it here. This proxy setting
  27. will not be included in the image, making it safe to use an `apt-cacher` or
  28. similar package for development.
  29. If you have Docker installed, you can set up a local apt caching proxy to
  30. like speed up subsequent builds like this:
  31. docker-compose up -d
  32. echo 'APT_PROXY=' >> config
  33. * `BASE_DIR` (Default: location of `build.sh`)
  34. **CAUTION**: Currently, changing this value will probably break build.sh
  35. Top-level directory for `pi-gen`. Contains stage directories, build
  36. scripts, and by default both work and deployment directories.
  37. * `WORK_DIR` (Default: `"$BASE_DIR/work"`)
  38. Directory in which `pi-gen` builds the target system. This value can be
  39. changed if you have a suitably large, fast storage location for stages to
  40. be built and cached. Note, `WORK_DIR` stores a complete copy of the target
  41. system for each build stage, amounting to tens of gigabytes in the case of
  42. Raspbian.
  43. **CAUTION**: If your working directory is on an NTFS partition you probably won't be able to build. Make sure this is a proper Linux filesystem.
  44. * `DEPLOY_DIR` (Default: `"$BASE_DIR/deploy"`)
  45. Output directory for target system images and NOOBS bundles.
  46. * `DEPLOY_ZIP` (Default: `1`)
  47. Setting to `0` will deploy the actual image (`.img`) instead of a zipped image (`.zip`).
  48. * `USE_QEMU` (Default: `"0"`)
  49. Setting to '1' enables the QEMU mode - creating an image that can be mounted via QEMU for an emulated
  50. environment. These images include "-qemu" in the image file name.
  51. * `LOCALE_DEFAULT` (Default: "en_GB.UTF-8" )
  52. Default system locale.
  53. * `TARGET_HOSTNAME` (Default: "raspberrypi" )
  54. Setting the hostname to the specified value.
  55. * `KEYBOARD_KEYMAP` (Default: "gb" )
  56. Default keyboard keymap.
  57. To get the current value from a running system, run `debconf-show
  58. keyboard-configuration` and look at the
  59. `keyboard-configuration/xkb-keymap` value.
  60. * `KEYBOARD_LAYOUT` (Default: "English (UK)" )
  61. Default keyboard layout.
  62. To get the current value from a running system, run `debconf-show
  63. keyboard-configuration` and look at the
  64. `keyboard-configuration/variant` value.
  65. * `TIMEZONE_DEFAULT` (Default: "Europe/London" )
  66. Default keyboard layout.
  67. To get the current value from a running system, look in
  68. `/etc/timezone`.
  69. * `FIRST_USER_NAME` (Default: "pi" )
  70. Username for the first user
  71. * `FIRST_USER_PASS` (Default: "raspberry")
  72. Password for the first user
  73. * `WPA_ESSID`, `WPA_PASSWORD` and `WPA_COUNTRY` (Default: unset)
  74. 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. If set, `WPA_PASSWORD` must be between 8 and 63 characters.
  75. * `ENABLE_SSH` (Default: `0`)
  76. 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.
  77. * `STAGE_LIST` (Default: `stage*`)
  78. 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.
  79. A simple example for building Raspbian:
  80. ```bash
  81. IMG_NAME='Raspbian'
  82. ```
  83. The config file can also be specified on the command line as an argument the `build.sh` or `build-docker.sh` scripts.
  84. ```
  85. ./build.sh -c myconfig
  86. ```
  87. This is parsed after `config` so can be used to override values set there.
  88. ## How the build process works
  89. The following process is followed to build images:
  90. * Loop through all of the stage directories in alphanumeric order
  91. * Move on to the next directory if this stage directory contains a file called
  92. "SKIP"
  93. * Run the script ```prerun.sh``` which is generally just used to copy the build
  94. directory between stages.
  95. * In each stage directory loop through each subdirectory and then run each of the
  96. install scripts it contains, again in alphanumeric order. These need to be named
  97. with a two digit padded number at the beginning.
  98. There are a number of different files and directories which can be used to
  99. control different parts of the build process:
  100. - **00-run.sh** - A unix shell script. Needs to be made executable for it to run.
  101. - **00-run-chroot.sh** - A unix shell script which will be run in the chroot
  102. of the image build directory. Needs to be made executable for it to run.
  103. - **00-debconf** - Contents of this file are passed to debconf-set-selections
  104. to configure things like locale, etc.
  105. - **00-packages** - A list of packages to install. Can have more than one, space
  106. separated, per line.
  107. - **00-packages-nr** - As 00-packages, except these will be installed using
  108. the ```--no-install-recommends -y``` parameters to apt-get.
  109. - **00-patches** - A directory containing patch files to be applied, using quilt.
  110. If a file named 'EDIT' is present in the directory, the build process will
  111. be interrupted with a bash session, allowing an opportunity to create/revise
  112. the patches.
  113. * If the stage directory contains files called "EXPORT_NOOBS" or "EXPORT_IMAGE" then
  114. add this stage to a list of images to generate
  115. * Generate the images for any stages that have specified them
  116. It is recommended to examine build.sh for finer details.
  117. ## Docker Build
  118. Docker can be used to perform the build inside a container. This partially isolates
  119. the build from the host system, and allows using the script on non-debian based
  120. systems (e.g. Fedora Linux). The isolate is not complete due to the need to use
  121. some kernel level services for arm emulation (binfmt) and loop devices (losetup).
  122. To build:
  123. ```bash
  124. vi config # Edit your config file. See above.
  125. ./build-docker.sh
  126. ```
  127. If everything goes well, your finished image will be in the `deploy/` folder.
  128. You can then remove the build container with `docker rm -v pigen_work`
  129. If something breaks along the line, you can edit the corresponding scripts, and
  130. continue:
  131. ```bash
  132. CONTINUE=1 ./build-docker.sh
  133. ```
  134. To examine the container after a failure you can enter a shell within it using:
  135. ```bash
  136. sudo docker run -it --privileged --volumes-from=pigen_work pi-gen /bin/bash
  137. ```
  138. 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
  139. ```bash
  140. PRESERVE_CONTAINER=1 ./build-docker.sh
  141. ```
  142. There is a possibility that even when running from a docker container, the
  143. installation of `qemu-user-static` will silently fail when building the image
  144. because `binfmt-support` _must be enabled on the underlying kernel_. An easy
  145. fix is to ensure `binfmt-support` is installed on the host machine before
  146. starting the `./build-docker.sh` script (or using your own docker build
  147. solution).
  148. ## Stage Anatomy
  149. ### Raspbian Stage Overview
  150. The build of Raspbian is divided up into several stages for logical clarity
  151. and modularity. This causes some initial complexity, but it simplifies
  152. maintenance and allows for more easy customization.
  153. - **Stage 0** - bootstrap. The primary purpose of this stage is to create a
  154. usable filesystem. This is accomplished largely through the use of
  155. `debootstrap`, which creates a minimal filesystem suitable for use as a
  156. base.tgz on Debian systems. This stage also configures apt settings and
  157. installs `raspberrypi-bootloader` which is missed by debootstrap. The
  158. minimal core is installed but not configured, and the system will not quite
  159. boot yet.
  160. - **Stage 1** - truly minimal system. This stage makes the system bootable by
  161. installing system files like `/etc/fstab`, configures the bootloader, makes
  162. the network operable, and installs packages like raspi-config. At this
  163. stage the system should boot to a local console from which you have the
  164. means to perform basic tasks needed to configure and install the system.
  165. This is as minimal as a system can possibly get, and its arguably not
  166. really usable yet in a traditional sense yet. Still, if you want minimal,
  167. this is minimal and the rest you could reasonably do yourself as sysadmin.
  168. - **Stage 2** - lite system. This stage produces the Raspbian-Lite image. It
  169. installs some optimized memory functions, sets timezone and charmap
  170. defaults, installs fake-hwclock and ntp, wifi and bluetooth support,
  171. dphys-swapfile, and other basics for managing the hardware. It also
  172. creates necessary groups and gives the pi user access to sudo and the
  173. standard console hardware permission groups.
  174. There are a few tools that may not make a whole lot of sense here for
  175. development purposes on a minimal system such as basic Python and Lua
  176. packages as well as the `build-essential` package. They are lumped right
  177. in with more essential packages presently, though they need not be with
  178. pi-gen. These are understandable for Raspbian's target audience, but if
  179. you were looking for something between truly minimal and Raspbian-Lite,
  180. here's where you start trimming.
  181. - **Stage 3** - desktop system. Here's where you get the full desktop system
  182. with X11 and LXDE, web browsers, git for development, Raspbian custom UI
  183. enhancements, etc. This is a base desktop system, with some development
  184. tools installed.
  185. - **Stage 4** - Normal Raspbian image. System meant to fit on a 4GB card. This is the
  186. stage that installs most things that make Raspbian friendly to new
  187. users like system documentation.
  188. - **Stage 5** - The Raspbian Full image. More development
  189. tools, an email client, learning tools like Scratch, specialized packages
  190. like sonic-pi, office productivity, etc.
  191. ### Stage specification
  192. If you wish to build up to a specified stage (such as building up to stage 2
  193. for a lite system), place an empty file named `SKIP` in each of the `./stage`
  194. directories you wish not to include.
  195. Then add an empty file named `SKIP_IMAGES` to `./stage4` and `./stage5` (if building up to stage 2) or
  196. to `./stage2` (if building a minimal system).
  197. ```bash
  198. # Example for building a lite system
  199. echo "IMG_NAME='Raspbian'" > config
  200. touch ./stage3/SKIP ./stage4/SKIP ./stage5/SKIP
  201. touch ./stage4/SKIP_IMAGES ./stage5/SKIP_IMAGES
  202. sudo ./build.sh # or ./build-docker.sh
  203. ```
  204. If you wish to build further configurations upon (for example) the lite
  205. system, you can also delete the contents of `./stage3` and `./stage4` and
  206. replace with your own contents in the same format.
  207. ## Skipping stages to speed up development
  208. If you're working on a specific stage the recommended development process is as
  209. follows:
  210. * Add a file called SKIP_IMAGES into the directories containing EXPORT_* files
  211. (currently stage2, stage4 and stage5)
  212. * Add SKIP files to the stages you don't want to build. For example, if you're
  213. basing your image on the lite image you would add these to stages 3, 4 and 5.
  214. * Run build.sh to build all stages
  215. * Add SKIP files to the earlier successfully built stages
  216. * Modify the last stage
  217. * Rebuild just the last stage using ```sudo CLEAN=1 ./build.sh```
  218. * Once you're happy with the image you can remove the SKIP_IMAGES files and
  219. export your image to test
  220. # Troubleshooting
  221. ## `64 Bit Systems`
  222. Please note there is currently an issue when compiling with a 64 Bit OS. See https://github.com/RPi-Distro/pi-gen/issues/271
  223. ## `binfmt_misc`
  224. Linux is able execute binaries from other architectures, meaning that it should be
  225. possible to make use of `pi-gen` on an x86_64 system, even though it will be running
  226. ARM binaries. This requires support from the [`binfmt_misc`](https://en.wikipedia.org/wiki/Binfmt_misc)
  227. kernel module.
  228. You may see the following error:
  229. ```
  230. update-binfmts: warning: Couldn't load the binfmt_misc module.
  231. ```
  232. To resolve this, ensure that the following files are available (install them if necessary):
  233. ```
  234. /lib/modules/$(uname -r)/kernel/fs/binfmt_misc.ko
  235. /usr/bin/qemu-arm-static
  236. ```
  237. You may also need to load the module by hand - run `modprobe binfmt_misc`.