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 version 2 of Windows Subsystem For Linux (WSL 2) to set
29      up a build host using Windows 10 or later, Windows Server 2019 or later.
30      See the :ref:`dev-manual/start:setting up to use windows subsystem for
31      linux (wsl 2)` section in the Yocto Project Development Tasks Manual
32      for more information.
33
34If you want more conceptual or background information on the Yocto
35Project, see the :doc:`/overview-manual/index`.
36
37Compatible Linux Distribution
38=============================
39
40Make sure your :term:`Build Host` meets the
41following requirements:
42
43-  50 Gbytes of free disk space
44
45-  Runs a supported Linux distribution (i.e. recent releases of Fedora,
46   openSUSE, CentOS, Debian, or Ubuntu). For a list of Linux
47   distributions that support the Yocto Project, see the
48   :ref:`ref-manual/system-requirements:supported linux distributions`
49   section in the Yocto Project Reference Manual. For detailed
50   information on preparing your build host, see the
51   :ref:`dev-manual/start:preparing the build host`
52   section in the Yocto Project Development Tasks Manual.
53
54-
55
56   -  Git &MIN_GIT_VERSION; or greater
57   -  tar &MIN_TAR_VERSION; or greater
58   -  Python &MIN_PYTHON_VERSION; or greater.
59   -  gcc &MIN_GCC_VERSION; or greater.
60   -  GNU make &MIN_MAKE_VERSION; or greater
61
62If your build host does not meet any of these three listed version
63requirements, you can take steps to prepare the system so that you
64can still use the Yocto Project. See the
65:ref:`ref-manual/system-requirements:required git, tar, python, make and gcc versions`
66section in the Yocto Project Reference Manual for information.
67
68Build Host Packages
69===================
70
71You must install essential host packages on your build host. The
72following command installs the host packages based on an Ubuntu
73distribution:
74
75.. code-block:: shell
76
77  $ sudo apt install &UBUNTU_HOST_PACKAGES_ESSENTIAL;
78
79.. note::
80
81   For host package requirements on all supported Linux distributions,
82   see the :ref:`ref-manual/system-requirements:required packages for the build host`
83   section in the Yocto Project Reference Manual.
84
85Use Git to Clone Poky
86=====================
87
88Once you complete the setup instructions for your machine, you need to
89get a copy of the Poky repository on your build host. Use the following
90commands to clone the Poky repository.
91
92.. code-block:: shell
93
94   $ git clone git://git.yoctoproject.org/poky
95   Cloning into 'poky'...
96   remote: Counting
97   objects: 432160, done. remote: Compressing objects: 100%
98   (102056/102056), done. remote: Total 432160 (delta 323116), reused
99   432037 (delta 323000) Receiving objects: 100% (432160/432160), 153.81 MiB | 8.54 MiB/s, done.
100   Resolving deltas: 100% (323116/323116), done.
101   Checking connectivity... done.
102
103Go to :yocto_wiki:`Releases wiki page </Releases>`, and choose a release
104codename (such as ``&DISTRO_NAME_NO_CAP;``), corresponding to either the
105latest stable release or a Long Term Support release.
106
107Then move to the ``poky`` directory and take a look at existing branches:
108
109.. code-block:: shell
110
111   $ cd poky
112   $ git branch -a
113   .
114   .
115   .
116   remotes/origin/HEAD -> origin/master
117   remotes/origin/dunfell
118   remotes/origin/dunfell-next
119   .
120   .
121   .
122   remotes/origin/gatesgarth
123   remotes/origin/gatesgarth-next
124   .
125   .
126   .
127   remotes/origin/master
128   remotes/origin/master-next
129   .
130   .
131   .
132
133
134For this example, check out the ``&DISTRO_NAME_NO_CAP;`` branch based on the
135``&DISTRO_NAME;`` release:
136
137.. code-block:: shell
138
139   $ git checkout -t origin/&DISTRO_NAME_NO_CAP; -b my-&DISTRO_NAME_NO_CAP;
140   Branch 'my-&DISTRO_NAME_NO_CAP;' set up to track remote branch '&DISTRO_NAME_NO_CAP;' from 'origin'.
141   Switched to a new branch 'my-&DISTRO_NAME_NO_CAP;'
142
143The previous Git checkout command creates a local branch named
144``my-&DISTRO_NAME_NO_CAP;``. The files available to you in that branch
145exactly match the repository's files in the ``&DISTRO_NAME_NO_CAP;``
146release branch.
147
148Note that you can regularly type the following command in the same directory
149to keep your local files in sync with the release branch:
150
151.. code-block:: shell
152
153   $ git pull
154
155For more options and information about accessing Yocto Project related
156repositories, see the
157:ref:`dev-manual/start:locating yocto project source files`
158section in the Yocto Project Development Tasks Manual.
159
160Building Your Image
161===================
162
163Use the following steps to build your image. The build process creates
164an entire Linux distribution, including the toolchain, from source.
165
166.. note::
167
168   -  If you are working behind a firewall and your build host is not
169      set up for proxies, you could encounter problems with the build
170      process when fetching source code (e.g. fetcher failures or Git
171      failures).
172
173   -  If you do not know your proxy settings, consult your local network
174      infrastructure resources and get that information. A good starting
175      point could also be to check your web browser settings. Finally,
176      you can find more information on the
177      ":yocto_wiki:`Working Behind a Network Proxy </Working_Behind_a_Network_Proxy>`"
178      page of the Yocto Project Wiki.
179
180#. **Initialize the Build Environment:** From within the ``poky``
181   directory, run the :ref:`ref-manual/structure:\`\`oe-init-build-env\`\``
182   environment
183   setup script to define Yocto Project's build environment on your
184   build host.
185
186   .. code-block:: shell
187
188      $ cd poky
189      $ source oe-init-build-env
190      You had no conf/local.conf file. This configuration file has therefore been
191      created for you with some default values. You may wish to edit it to, for
192      example, select a different MACHINE (target hardware). See conf/local.conf
193      for more information as common configuration options are commented.
194
195      You had no conf/bblayers.conf file. This configuration file has therefore
196      been created for you with some default values. To add additional metadata
197      layers into your configuration please add entries to conf/bblayers.conf.
198
199      The Yocto Project has extensive documentation about OE including a reference
200      manual which can be found at:
201          https://docs.yoctoproject.org
202
203      For more information about OpenEmbedded see their website:
204          https://www.openembedded.org/
205
206      ### Shell environment set up for builds. ###
207
208      You can now run 'bitbake <target>'
209
210      Common targets are:
211          core-image-minimal
212          core-image-full-cmdline
213          core-image-sato
214          core-image-weston
215          meta-toolchain
216          meta-ide-support
217
218      You can also run generated QEMU images with a command like 'runqemu qemux86-64'
219
220      Other commonly useful commands are:
221       - 'devtool' and 'recipetool' handle common recipe tasks
222       - 'bitbake-layers' handles common layer tasks
223       - 'oe-pkgdata-util' handles common target package tasks
224
225   Among other things, the script creates the :term:`Build Directory`, which is
226   ``build`` in this case and is located in the :term:`Source Directory`.  After
227   the script runs, your current working directory is set to the
228   :term:`Build Directory`. Later, when the build completes, the
229   :term:`Build Directory` contains all the files created during the build.
230
231#. **Examine Your Local Configuration File:** When you set up the build
232   environment, a local configuration file named ``local.conf`` becomes
233   available in a ``conf`` subdirectory of the :term:`Build Directory`. For this
234   example, the defaults are set to build for a ``qemux86`` target,
235   which is suitable for emulation. The package manager used is set to
236   the RPM package manager.
237
238   .. tip::
239
240      You can significantly speed up your build and guard against fetcher
241      failures by using :ref:`overview-manual/concepts:shared state cache`
242      mirrors and enabling :ref:`overview-manual/concepts:hash equivalence`.
243      This way, you can use pre-built artifacts rather than building them.
244      This is relevant only when your network and the server that you use
245      can download these artifacts faster than you would be able to build them.
246
247      To use such mirrors, uncomment the below lines in your ``conf/local.conf``
248      file in the :term:`Build Directory`::
249
250         BB_SIGNATURE_HANDLER = "OEEquivHash"
251         BB_HASHSERVE = "auto"
252         BB_HASHSERVE_UPSTREAM = "hashserv.yocto.io:8687"
253         SSTATE_MIRRORS ?= "file://.* https://sstate.yoctoproject.org/all/PATH;downloadfilename=PATH"
254
255#. **Start the Build:** Continue with the following command to build an OS
256   image for the target, which is ``core-image-sato`` in this example:
257
258   .. code-block:: shell
259
260      $ bitbake core-image-sato
261
262   For information on using the ``bitbake`` command, see the
263   :ref:`overview-manual/concepts:bitbake` section in the Yocto Project Overview and
264   Concepts Manual, or see
265   :ref:`bitbake:bitbake-user-manual/bitbake-user-manual-intro:the bitbake command`
266   in the BitBake User Manual.
267
268#. **Simulate Your Image Using QEMU:** Once this particular image is
269   built, you can start QEMU, which is a Quick EMUlator that ships with
270   the Yocto Project:
271
272   .. code-block:: shell
273
274      $ runqemu qemux86-64
275
276   If you want to learn more about running QEMU, see the
277   :ref:`dev-manual/qemu:using the quick emulator (qemu)` chapter in
278   the Yocto Project Development Tasks Manual.
279
280#. **Exit QEMU:** Exit QEMU by either clicking on the shutdown icon or by typing
281   ``Ctrl-C`` in the QEMU transcript window from which you evoked QEMU.
282
283Customizing Your Build for Specific Hardware
284============================================
285
286So far, all you have done is quickly built an image suitable for
287emulation only. This section shows you how to customize your build for
288specific hardware by adding a hardware layer into the Yocto Project
289development environment.
290
291In general, layers are repositories that contain related sets of
292instructions and configurations that tell the Yocto Project what to do.
293Isolating related metadata into functionally specific layers facilitates
294modular development and makes it easier to reuse the layer metadata.
295
296.. note::
297
298   By convention, layer names start with the string "meta-".
299
300Follow these steps to add a hardware layer:
301
302#. **Find a Layer:** Many hardware layers are available. The Yocto Project
303   :yocto_git:`Source Repositories <>` has many hardware layers.
304   This example adds the
305   `meta-altera <https://github.com/kraj/meta-altera>`__ hardware layer.
306
307#. **Clone the Layer:** Use Git to make a local copy of the layer on your
308   machine. You can put the copy in the top level of the copy of the
309   Poky repository created earlier:
310
311   .. code-block:: shell
312
313      $ cd poky
314      $ git clone https://github.com/kraj/meta-altera.git
315      Cloning into 'meta-altera'...
316      remote: Counting objects: 25170, done.
317      remote: Compressing objects: 100% (350/350), done.
318      remote: Total 25170 (delta 645), reused 719 (delta 538), pack-reused 24219
319      Receiving objects: 100% (25170/25170), 41.02 MiB | 1.64 MiB/s, done.
320      Resolving deltas: 100% (13385/13385), done.
321      Checking connectivity... done.
322
323   The hardware layer is now available
324   next to other layers inside the Poky reference repository on your build
325   host as ``meta-altera`` and contains all the metadata needed to
326   support hardware from Altera, which is owned by Intel.
327
328   .. note::
329
330      It is recommended for layers to have a branch per Yocto Project release.
331      Please make sure to checkout the layer branch supporting the Yocto Project
332      release you're using.
333
334#. **Change the Configuration to Build for a Specific Machine:** The
335   :term:`MACHINE` variable in the
336   ``local.conf`` file specifies the machine for the build. For this
337   example, set the :term:`MACHINE` variable to ``cyclone5``. These
338   configurations are used:
339   https://github.com/kraj/meta-altera/blob/master/conf/machine/cyclone5.conf.
340
341   .. note::
342
343      See the "Examine Your Local Configuration File" step earlier for more
344      information on configuring the build.
345
346#. **Add Your Layer to the Layer Configuration File:** Before you can use
347   a layer during a build, you must add it to your ``bblayers.conf``
348   file, which is found in the :term:`Build Directory` ``conf`` directory.
349
350   Use the ``bitbake-layers add-layer`` command to add the layer to the
351   configuration file:
352
353   .. code-block:: shell
354
355      $ cd poky/build
356      $ bitbake-layers add-layer ../meta-altera
357      NOTE: Starting bitbake server...
358      Parsing recipes: 100% |##################################################################| Time: 0:00:32
359      Parsing of 918 .bb files complete (0 cached, 918 parsed). 1401 targets,
360      123 skipped, 0 masked, 0 errors.
361
362   You can find
363   more information on adding layers in the
364   :ref:`dev-manual/common-tasks:adding a layer using the \`\`bitbake-layers\`\` script`
365   section.
366
367Completing these steps has added the ``meta-altera`` layer to your Yocto
368Project development environment and configured it to build for the
369``cyclone5`` machine.
370
371.. note::
372
373   The previous steps are for demonstration purposes only. If you were
374   to attempt to build an image for the ``cyclone5`` machine, you should
375   read the Altera ``README``.
376
377Creating Your Own General Layer
378===============================
379
380Maybe you have an application or specific set of behaviors you need to
381isolate. You can create your own general layer using the
382``bitbake-layers create-layer`` command. The tool automates layer
383creation by setting up a subdirectory with a ``layer.conf``
384configuration file, a ``recipes-example`` subdirectory that contains an
385``example.bb`` recipe, a licensing file, and a ``README``.
386
387The following commands run the tool to create a layer named
388``meta-mylayer`` in the ``poky`` directory:
389
390.. code-block:: shell
391
392   $ cd poky
393   $ bitbake-layers create-layer meta-mylayer
394   NOTE: Starting bitbake server...
395   Add your new layer with 'bitbake-layers add-layer meta-mylayer'
396
397For more information
398on layers and how to create them, see the
399:ref:`dev-manual/common-tasks:creating a general layer using the \`\`bitbake-layers\`\` script`
400section in the Yocto Project Development Tasks Manual.
401
402Where To Go Next
403================
404
405Now that you have experienced using the Yocto Project, you might be
406asking yourself "What now?". The Yocto Project has many sources of
407information including the website, wiki pages, and user manuals:
408
409-  **Website:** The :yocto_home:`Yocto Project Website <>` provides
410   background information, the latest builds, breaking news, full
411   development documentation, and access to a rich Yocto Project
412   Development Community into which you can tap.
413
414-  **Video Seminar:** The `Introduction to the Yocto Project and BitBake, Part 1
415   <https://youtu.be/yuE7my3KOpo>`__ and
416   `Introduction to the Yocto Project and BitBake, Part 2
417   <https://youtu.be/iZ05TTyzGHk>`__ videos offer a video seminar
418   introducing you to the most important aspects of developing a
419   custom embedded Linux distribution with the Yocto Project.
420
421-  **Yocto Project Overview and Concepts Manual:** The
422   :doc:`/overview-manual/index` is a great
423   place to start to learn about the Yocto Project. This manual
424   introduces you to the Yocto Project and its development environment.
425   The manual also provides conceptual information for various aspects
426   of the Yocto Project.
427
428-  **Yocto Project Wiki:** The :yocto_wiki:`Yocto Project Wiki <>`
429   provides additional information on where to go next when ramping up
430   with the Yocto Project, release information, project planning, and QA
431   information.
432
433-  **Yocto Project Mailing Lists:** Related mailing lists provide a forum
434   for discussion, patch submission and announcements. There are several
435   mailing lists grouped by topic. See the
436   :ref:`ref-manual/resources:mailing lists`
437   section in the Yocto Project Reference Manual for a complete list of
438   Yocto Project mailing lists.
439
440-  **Comprehensive List of Links and Other Documentation:** The
441   :ref:`ref-manual/resources:links and related documentation`
442   section in the Yocto Project Reference Manual provides a
443   comprehensive list of all related links and other user documentation.
444
445.. include:: /boilerplate.rst
446