1.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
2
3=========================
4Yocto Project Quick Build
5=========================
6
7Welcome!
8========
9
10This short document steps you through the process for a typical
11image build using the Yocto Project. The document also introduces how to
12configure a build for specific hardware. You will use Yocto Project to
13build a reference embedded OS called Poky.
14
15.. note::
16
17   -  The examples in this paper assume you are using a native Linux
18      system running a recent Ubuntu Linux distribution. If the machine
19      you want to use Yocto Project on to build an image
20      (:term:`Build Host`) is not
21      a native Linux system, you can still perform these steps by using
22      CROss PlatformS (CROPS) and setting up a Poky container. See the
23      :ref:`dev-manual/start:setting up to use cross platforms (crops)`
24      section
25      in the Yocto Project Development Tasks Manual for more
26      information.
27
28   -  You may use Windows Subsystem For Linux v2 to set up a build host
29      using Windows 10.
30
31      .. note::
32
33         The Yocto Project is not compatible with WSLv1, it is
34         compatible but not officially supported nor validated with
35         WSLv2, if you still decide to use WSL please upgrade to WSLv2.
36
37      See the :ref:`dev-manual/start:setting up to use windows
38      subsystem for linux (wslv2)` section in the Yocto Project Development
39      Tasks Manual for more information.
40
41If you want more conceptual or background information on the Yocto
42Project, see the :doc:`/overview-manual/index`.
43
44Compatible Linux Distribution
45=============================
46
47Make sure your :term:`Build Host` meets the
48following requirements:
49
50-  50 Gbytes of free disk space
51
52-  Runs a supported Linux distribution (i.e. recent releases of Fedora,
53   openSUSE, CentOS, Debian, or Ubuntu). For a list of Linux
54   distributions that support the Yocto Project, see the
55   :ref:`ref-manual/system-requirements:supported linux distributions`
56   section in the Yocto Project Reference Manual. For detailed
57   information on preparing your build host, see the
58   :ref:`dev-manual/start:preparing the build host`
59   section in the Yocto Project Development Tasks Manual.
60
61-
62
63   -  Git &MIN_GIT_VERSION; or greater
64   -  tar &MIN_TAR_VERSION; or greater
65   -  Python &MIN_PYTHON_VERSION; or greater.
66   -  gcc &MIN_GCC_VERSION; or greater.
67
68If your build host does not meet any of these three listed version
69requirements, you can take steps to prepare the system so that you
70can still use the Yocto Project. See the
71:ref:`ref-manual/system-requirements:required git, tar, python and gcc versions`
72section in the Yocto Project Reference Manual for information.
73
74Build Host Packages
75===================
76
77You must install essential host packages on your build host. The
78following command installs the host packages based on an Ubuntu
79distribution:
80
81.. code-block:: shell
82
83  $ sudo apt install &UBUNTU_HOST_PACKAGES_ESSENTIAL;
84
85.. note::
86
87   For host package requirements on all supported Linux distributions,
88   see the :ref:`ref-manual/system-requirements:required packages for the build host`
89   section in the Yocto Project Reference Manual.
90
91Use Git to Clone Poky
92=====================
93
94Once you complete the setup instructions for your machine, you need to
95get a copy of the Poky repository on your build host. Use the following
96commands to clone the Poky repository.
97
98.. code-block:: shell
99
100   $ git clone git://git.yoctoproject.org/poky
101   Cloning into 'poky'...
102   remote: Counting
103   objects: 432160, done. remote: Compressing objects: 100%
104   (102056/102056), done. remote: Total 432160 (delta 323116), reused
105   432037 (delta 323000) Receiving objects: 100% (432160/432160), 153.81 MiB | 8.54 MiB/s, done.
106   Resolving deltas: 100% (323116/323116), done.
107   Checking connectivity... done.
108
109Go to :yocto_wiki:`Releases wiki page </Releases>`, and choose a release
110codename (such as ``&DISTRO_NAME_NO_CAP;``), corresponding to either the
111latest stable release or a Long Term Support release.
112
113Then move to the ``poky`` directory and take a look at existing branches:
114
115.. code-block:: shell
116
117   $ cd poky
118   $ git branch -a
119   .
120   .
121   .
122   remotes/origin/HEAD -> origin/master
123   remotes/origin/dunfell
124   remotes/origin/dunfell-next
125   .
126   .
127   .
128   remotes/origin/gatesgarth
129   remotes/origin/gatesgarth-next
130   .
131   .
132   .
133   remotes/origin/master
134   remotes/origin/master-next
135   .
136   .
137   .
138
139
140For this example, check out the ``&DISTRO_NAME_NO_CAP;`` branch based on the
141``&DISTRO_NAME;`` release:
142
143.. code-block:: shell
144
145   $ git checkout -t origin/&DISTRO_NAME_NO_CAP; -b my-&DISTRO_NAME_NO_CAP;
146   Branch 'my-&DISTRO_NAME_NO_CAP;' set up to track remote branch '&DISTRO_NAME_NO_CAP;' from 'origin'.
147   Switched to a new branch 'my-&DISTRO_NAME_NO_CAP;'
148
149The previous Git checkout command creates a local branch named
150``my-&DISTRO_NAME_NO_CAP;``. The files available to you in that branch
151exactly match the repository's files in the ``&DISTRO_NAME_NO_CAP;``
152release branch.
153
154Note that you can regularly type the following command in the same directory
155to keep your local files in sync with the release branch:
156
157.. code-block:: shell
158
159   $ git pull
160
161For more options and information about accessing Yocto Project related
162repositories, see the
163:ref:`dev-manual/start:locating yocto project source files`
164section in the Yocto Project Development Tasks Manual.
165
166Building Your Image
167===================
168
169Use the following steps to build your image. The build process creates
170an entire Linux distribution, including the toolchain, from source.
171
172.. note::
173
174   -  If you are working behind a firewall and your build host is not
175      set up for proxies, you could encounter problems with the build
176      process when fetching source code (e.g. fetcher failures or Git
177      failures).
178
179   -  If you do not know your proxy settings, consult your local network
180      infrastructure resources and get that information. A good starting
181      point could also be to check your web browser settings. Finally,
182      you can find more information on the
183      ":yocto_wiki:`Working Behind a Network Proxy </Working_Behind_a_Network_Proxy>`"
184      page of the Yocto Project Wiki.
185
186#. **Initialize the Build Environment:** From within the ``poky``
187   directory, run the :ref:`ref-manual/structure:\`\`oe-init-build-env\`\``
188   environment
189   setup script to define Yocto Project's build environment on your
190   build host.
191
192   .. code-block:: shell
193
194      $ cd poky
195      $ source oe-init-build-env
196      You had no conf/local.conf file. This configuration file has therefore been
197      created for you with some default values. You may wish to edit it to, for
198      example, select a different MACHINE (target hardware). See conf/local.conf
199      for more information as common configuration options are commented.
200
201      You had no conf/bblayers.conf file. This configuration file has therefore
202      been created for you with some default values. To add additional metadata
203      layers into your configuration please add entries to conf/bblayers.conf.
204
205      The Yocto Project has extensive documentation about OE including a reference
206      manual which can be found at:
207          https://docs.yoctoproject.org
208
209      For more information about OpenEmbedded see their website:
210          https://www.openembedded.org/
211
212      ### Shell environment set up for builds. ###
213
214      You can now run 'bitbake <target>'
215
216      Common targets are:
217          core-image-minimal
218          core-image-full-cmdline
219          core-image-sato
220          core-image-weston
221          meta-toolchain
222          meta-ide-support
223
224      You can also run generated QEMU images with a command like 'runqemu qemux86-64'
225
226      Other commonly useful commands are:
227       - 'devtool' and 'recipetool' handle common recipe tasks
228       - 'bitbake-layers' handles common layer tasks
229       - 'oe-pkgdata-util' handles common target package tasks
230
231   Among other things, the script creates the :term:`Build Directory`, which is
232   ``build`` in this case and is located in the :term:`Source Directory`.  After
233   the script runs, your current working directory is set to the Build
234   Directory. Later, when the build completes, the Build Directory contains all the
235   files created during the build.
236
237#. **Examine Your Local Configuration File:** When you set up the build
238   environment, a local configuration file named ``local.conf`` becomes
239   available in a ``conf`` subdirectory of the Build Directory. For this
240   example, the defaults are set to build for a ``qemux86`` target,
241   which is suitable for emulation. The package manager used is set to
242   the RPM package manager.
243
244   .. tip::
245
246      You can significantly speed up your build and guard against fetcher
247      failures by using :ref:`overview-manual/concepts:shared state cache`
248      mirrors and enabling :ref:`overview-manual/concepts:hash equivalence`.
249      This way, you can use pre-built artifacts rather than building them.
250      This is relevant only when your network and the server that you use
251      can download these artifacts faster than you would be able to build them.
252
253      To use such mirrors, uncomment the below lines in your ``local.conf``
254      file in the :term:`Build Directory`::
255
256         BB_SIGNATURE_HANDLER = "OEEquivHash"
257         BB_HASHSERVE = "auto"
258         BB_HASHSERVE_UPSTREAM = "typhoon.yocto.io:8687"
259         SSTATE_MIRRORS ?= "file://.* https://sstate.yoctoproject.org/&YOCTO_DOC_VERSION;/PATH;downloadfilename=PATH"
260
261      The above settings assumed the use of Yocto Project &YOCTO_DOC_VERSION;.
262      If you are using the development version instead, set :term:`SSTATE_MIRRORS` as follows::
263
264         SSTATE_MIRRORS ?= "file://.* https://sstate.yoctoproject.org/dev/PATH;downloadfilename=PATH"
265
266#. **Start the Build:** Continue with the following command to build an OS
267   image for the target, which is ``core-image-sato`` in this example:
268
269   .. code-block:: shell
270
271      $ bitbake core-image-sato
272
273   For information on using the ``bitbake`` command, see the
274   :ref:`overview-manual/concepts:bitbake` section in the Yocto Project Overview and
275   Concepts Manual, or see
276   :ref:`bitbake:bitbake-user-manual/bitbake-user-manual-intro:the bitbake command`
277   in the BitBake User Manual.
278
279#. **Simulate Your Image Using QEMU:** Once this particular image is
280   built, you can start QEMU, which is a Quick EMUlator that ships with
281   the Yocto Project:
282
283   .. code-block:: shell
284
285      $ runqemu qemux86-64
286
287   If you want to learn more about running QEMU, see the
288   :ref:`dev-manual/qemu:using the quick emulator (qemu)` chapter in
289   the Yocto Project Development Tasks Manual.
290
291#. **Exit QEMU:** Exit QEMU by either clicking on the shutdown icon or by typing
292   ``Ctrl-C`` in the QEMU transcript window from which you evoked QEMU.
293
294Customizing Your Build for Specific Hardware
295============================================
296
297So far, all you have done is quickly built an image suitable for
298emulation only. This section shows you how to customize your build for
299specific hardware by adding a hardware layer into the Yocto Project
300development environment.
301
302In general, layers are repositories that contain related sets of
303instructions and configurations that tell the Yocto Project what to do.
304Isolating related metadata into functionally specific layers facilitates
305modular development and makes it easier to reuse the layer metadata.
306
307.. note::
308
309   By convention, layer names start with the string "meta-".
310
311Follow these steps to add a hardware layer:
312
313#. **Find a Layer:** Many hardware layers are available. The Yocto Project
314   :yocto_git:`Source Repositories <>` has many hardware layers.
315   This example adds the
316   `meta-altera <https://github.com/kraj/meta-altera>`__ hardware layer.
317
318#. **Clone the Layer:** Use Git to make a local copy of the layer on your
319   machine. You can put the copy in the top level of the copy of the
320   Poky repository created earlier:
321
322   .. code-block:: shell
323
324      $ cd poky
325      $ git clone https://github.com/kraj/meta-altera.git
326      Cloning into 'meta-altera'...
327      remote: Counting objects: 25170, done.
328      remote: Compressing objects: 100% (350/350), done.
329      remote: Total 25170 (delta 645), reused 719 (delta 538), pack-reused 24219
330      Receiving objects: 100% (25170/25170), 41.02 MiB | 1.64 MiB/s, done.
331      Resolving deltas: 100% (13385/13385), done.
332      Checking connectivity... done.
333
334   The hardware layer is now available
335   next to other layers inside the Poky reference repository on your build
336   host as ``meta-altera`` and contains all the metadata needed to
337   support hardware from Altera, which is owned by Intel.
338
339   .. note::
340
341      It is recommended for layers to have a branch per Yocto Project release.
342      Please make sure to checkout the layer branch supporting the Yocto Project
343      release you're using.
344
345#. **Change the Configuration to Build for a Specific Machine:** The
346   :term:`MACHINE` variable in the
347   ``local.conf`` file specifies the machine for the build. For this
348   example, set the :term:`MACHINE` variable to ``cyclone5``. These
349   configurations are used:
350   https://github.com/kraj/meta-altera/blob/master/conf/machine/cyclone5.conf.
351
352   .. note::
353
354      See the "Examine Your Local Configuration File" step earlier for more
355      information on configuring the build.
356
357#. **Add Your Layer to the Layer Configuration File:** Before you can use
358   a layer during a build, you must add it to your ``bblayers.conf``
359   file, which is found in the
360   :term:`Build Directory` ``conf``
361   directory.
362
363   Use the ``bitbake-layers add-layer`` command to add the layer to the
364   configuration file:
365
366   .. code-block:: shell
367
368      $ cd poky/build
369      $ bitbake-layers add-layer ../meta-altera
370      NOTE: Starting bitbake server...
371      Parsing recipes: 100% |##################################################################| Time: 0:00:32
372      Parsing of 918 .bb files complete (0 cached, 918 parsed). 1401 targets,
373      123 skipped, 0 masked, 0 errors.
374
375   You can find
376   more information on adding layers in the
377   :ref:`dev-manual/common-tasks:adding a layer using the \`\`bitbake-layers\`\` script`
378   section.
379
380Completing these steps has added the ``meta-altera`` layer to your Yocto
381Project development environment and configured it to build for the
382``cyclone5`` machine.
383
384.. note::
385
386   The previous steps are for demonstration purposes only. If you were
387   to attempt to build an image for the ``cyclone5`` machine, you should
388   read the Altera ``README``.
389
390Creating Your Own General Layer
391===============================
392
393Maybe you have an application or specific set of behaviors you need to
394isolate. You can create your own general layer using the
395``bitbake-layers create-layer`` command. The tool automates layer
396creation by setting up a subdirectory with a ``layer.conf``
397configuration file, a ``recipes-example`` subdirectory that contains an
398``example.bb`` recipe, a licensing file, and a ``README``.
399
400The following commands run the tool to create a layer named
401``meta-mylayer`` in the ``poky`` directory:
402
403.. code-block:: shell
404
405   $ cd poky
406   $ bitbake-layers create-layer meta-mylayer
407   NOTE: Starting bitbake server...
408   Add your new layer with 'bitbake-layers add-layer meta-mylayer'
409
410For more information
411on layers and how to create them, see the
412:ref:`dev-manual/common-tasks:creating a general layer using the \`\`bitbake-layers\`\` script`
413section in the Yocto Project Development Tasks Manual.
414
415Where To Go Next
416================
417
418Now that you have experienced using the Yocto Project, you might be
419asking yourself "What now?". The Yocto Project has many sources of
420information including the website, wiki pages, and user manuals:
421
422-  **Website:** The :yocto_home:`Yocto Project Website <>` provides
423   background information, the latest builds, breaking news, full
424   development documentation, and access to a rich Yocto Project
425   Development Community into which you can tap.
426
427-  **Video Seminar:** The `Introduction to the Yocto Project and Bitbake, Part 1
428   <https://youtu.be/yuE7my3KOpo>`__ and
429   `Introduction to the Yocto Project and Bitbake, Part 2
430   <https://youtu.be/iZ05TTyzGHk>`__ videos offer a video seminar
431   introducing you to the most important aspects of developing a
432   custom embedded Linux distribution with the Yocto Project.
433
434-  **Yocto Project Overview and Concepts Manual:** The
435   :doc:`/overview-manual/index` is a great
436   place to start to learn about the Yocto Project. This manual
437   introduces you to the Yocto Project and its development environment.
438   The manual also provides conceptual information for various aspects
439   of the Yocto Project.
440
441-  **Yocto Project Wiki:** The :yocto_wiki:`Yocto Project Wiki <>`
442   provides additional information on where to go next when ramping up
443   with the Yocto Project, release information, project planning, and QA
444   information.
445
446-  **Yocto Project Mailing Lists:** Related mailing lists provide a forum
447   for discussion, patch submission and announcements. There are several
448   mailing lists grouped by topic. See the
449   :ref:`ref-manual/resources:mailing lists`
450   section in the Yocto Project Reference Manual for a complete list of
451   Yocto Project mailing lists.
452
453-  **Comprehensive List of Links and Other Documentation:** The
454   :ref:`ref-manual/resources:links and related documentation`
455   section in the Yocto Project Reference Manual provides a
456   comprehensive list of all related links and other user documentation.
457
458.. include:: /boilerplate.rst
459