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