Yocto Project Quick Build¶
This short document steps you through the process for a typical image build using the Yocto Project. The document also introduces how to configure a build for specific hardware. You will use Yocto Project to build a reference embedded OS called Poky.
The examples in this paper assume you are using a native Linux system running a recent Ubuntu Linux distribution. If the machine you want to use Yocto Project on to build an image (Build Host) is not a native Linux system, you can still perform these steps by using CROss PlatformS (CROPS) and setting up a Poky container. See the Setting Up to Use CROss PlatformS (CROPS) section in the Yocto Project Development Tasks Manual for more information.
You may use Windows Subsystem For Linux v2 to set up a build host using Windows 10.
The Yocto Project is not compatible with WSLv1, it is compatible but not officially supported nor validated with WSLv2, if you still decide to use WSL please upgrade to WSLv2.
See the Setting Up to Use Windows Subsystem For Linux (WSLv2) section in the Yocto Project Development Tasks Manual for more information.
If you want more conceptual or background information on the Yocto Project, see the Yocto Project Overview and Concepts Manual.
Compatible Linux Distribution¶
Make sure your Build Host meets the following requirements:
50 Gbytes of free disk space
Runs a supported Linux distribution (i.e. recent releases of Fedora, openSUSE, CentOS, Debian, or Ubuntu). For a list of Linux distributions that support the Yocto Project, see the Supported Linux Distributions section in the Yocto Project Reference Manual. For detailed information on preparing your build host, see the Preparing the Build Host section in the Yocto Project Development Tasks Manual.
Git 220.127.116.11 or greater
tar 1.28 or greater
Python 3.6.0 or greater.
gcc 5.0 or greater.
If your build host does not meet any of these three listed version requirements, you can take steps to prepare the system so that you can still use the Yocto Project. See the Required Git, tar, Python and gcc Versions section in the Yocto Project Reference Manual for information.
Build Host Packages¶
You must install essential host packages on your build host. The following command installs the host packages based on an Ubuntu distribution:
$ sudo apt install gawk wget git diffstat unzip texinfo gcc build-essential chrpath socat cpio python3 python3-pip python3-pexpect xz-utils debianutils iputils-ping python3-git python3-jinja2 libegl1-mesa libsdl1.2-dev pylint3 xterm python3-subunit mesa-common-dev zstd liblz4-tool
For host package requirements on all supported Linux distributions, see the Required Packages for the Build Host section in the Yocto Project Reference Manual.
Use Git to Clone Poky¶
Once you complete the setup instructions for your machine, you need to get a copy of the Poky repository on your build host. Use the following commands to clone the Poky repository.
$ git clone git://git.yoctoproject.org/poky Cloning into 'poky'... remote: Counting objects: 432160, done. remote: Compressing objects: 100% (102056/102056), done. remote: Total 432160 (delta 323116), reused 432037 (delta 323000) Receiving objects: 100% (432160/432160), 153.81 MiB | 8.54 MiB/s, done. Resolving deltas: 100% (323116/323116), done. Checking connectivity... done.
Go to Releases wiki page, and choose a release
codename (such as
kirkstone), corresponding to either the
latest stable release or a Long Term Support release.
Then move to the
poky directory and take a look at existing branches:
$ cd poky $ git branch -a . . . remotes/origin/HEAD -> origin/master remotes/origin/dunfell remotes/origin/dunfell-next . . . remotes/origin/gatesgarth remotes/origin/gatesgarth-next . . . remotes/origin/master remotes/origin/master-next . . .
For this example, check out the
kirkstone branch based on the
$ git checkout -t origin/kirkstone -b my-kirkstone Branch 'my-kirkstone' set up to track remote branch 'kirkstone' from 'origin'. Switched to a new branch 'my-kirkstone'
The previous Git checkout command creates a local branch named
my-kirkstone. The files available to you in that branch
exactly match the repository’s files in the
Note that you can regularly type the following command in the same directory to keep your local files in sync with the release branch:
$ git pull
For more options and information about accessing Yocto Project related repositories, see the Locating Yocto Project Source Files section in the Yocto Project Development Tasks Manual.
Building Your Image¶
Use the following steps to build your image. The build process creates an entire Linux distribution, including the toolchain, from source.
If you are working behind a firewall and your build host is not set up for proxies, you could encounter problems with the build process when fetching source code (e.g. fetcher failures or Git failures).
If you do not know your proxy settings, consult your local network infrastructure resources and get that information. A good starting point could also be to check your web browser settings. Finally, you can find more information on the “Working Behind a Network Proxy” page of the Yocto Project Wiki.
Initialize the Build Environment: From within the
pokydirectory, run the oe-init-build-env environment setup script to define Yocto Project’s build environment on your build host.
$ cd poky $ source oe-init-build-env You had no conf/local.conf file. This configuration file has therefore been created for you with some default values. You may wish to edit it to, for example, select a different MACHINE (target hardware). See conf/local.conf for more information as common configuration options are commented. You had no conf/bblayers.conf file. This configuration file has therefore been created for you with some default values. To add additional metadata layers into your configuration please add entries to conf/bblayers.conf. The Yocto Project has extensive documentation about OE including a reference manual which can be found at: https://docs.yoctoproject.org For more information about OpenEmbedded see their website: https://www.openembedded.org/ ### Shell environment set up for builds. ### You can now run 'bitbake <target>' Common targets are: core-image-minimal core-image-full-cmdline core-image-sato core-image-weston meta-toolchain meta-ide-support You can also run generated QEMU images with a command like 'runqemu qemux86-64' Other commonly useful commands are: - 'devtool' and 'recipetool' handle common recipe tasks - 'bitbake-layers' handles common layer tasks - 'oe-pkgdata-util' handles common target package tasks
Among other things, the script creates the Build Directory, which is
buildin this case and is located in the Source Directory. After the script runs, your current working directory is set to the Build Directory. Later, when the build completes, the Build Directory contains all the files created during the build.
Examine Your Local Configuration File: When you set up the build environment, a local configuration file named
local.confbecomes available in a
confsubdirectory of the Build Directory. For this example, the defaults are set to build for a
qemux86target, which is suitable for emulation. The package manager used is set to the RPM package manager.
You can significantly speed up your build and guard against fetcher failures by using Shared State Cache mirrors and enabling Hash Equivalence. This way, you can use pre-built artifacts rather than building them. This is relevant only when your network and the server that you use can download these artifacts faster than you would be able to build them.
To use such mirrors, uncomment the below lines in your
conf/local.conffile in the Build Directory:
BB_SIGNATURE_HANDLER = "OEEquivHash" BB_HASHSERVE = "auto" BB_HASHSERVE_UPSTREAM = "typhoon.yocto.io:8687" SSTATE_MIRRORS ?= "file://.* https://sstate.yoctoproject.org/4.0.1/PATH;downloadfilename=PATH"
The above settings assumed the use of Yocto Project 4.0.1. If you are using the development version instead, set SSTATE_MIRRORS as follows:
SSTATE_MIRRORS ?= "file://.* https://sstate.yoctoproject.org/dev/PATH;downloadfilename=PATH"
Start the Build: Continue with the following command to build an OS image for the target, which is
core-image-satoin this example:
$ bitbake core-image-sato
Simulate Your Image Using QEMU: Once this particular image is built, you can start QEMU, which is a Quick EMUlator that ships with the Yocto Project:
$ runqemu qemux86-64
If you want to learn more about running QEMU, see the Using the Quick EMUlator (QEMU) chapter in the Yocto Project Development Tasks Manual.
Exit QEMU: Exit QEMU by either clicking on the shutdown icon or by typing
Ctrl-Cin the QEMU transcript window from which you evoked QEMU.
Customizing Your Build for Specific Hardware¶
So far, all you have done is quickly built an image suitable for emulation only. This section shows you how to customize your build for specific hardware by adding a hardware layer into the Yocto Project development environment.
In general, layers are repositories that contain related sets of instructions and configurations that tell the Yocto Project what to do. Isolating related metadata into functionally specific layers facilitates modular development and makes it easier to reuse the layer metadata.
By convention, layer names start with the string “meta-“.
Follow these steps to add a hardware layer:
Clone the Layer: Use Git to make a local copy of the layer on your machine. You can put the copy in the top level of the copy of the Poky repository created earlier:
$ cd poky $ git clone https://github.com/kraj/meta-altera.git Cloning into 'meta-altera'... remote: Counting objects: 25170, done. remote: Compressing objects: 100% (350/350), done. remote: Total 25170 (delta 645), reused 719 (delta 538), pack-reused 24219 Receiving objects: 100% (25170/25170), 41.02 MiB | 1.64 MiB/s, done. Resolving deltas: 100% (13385/13385), done. Checking connectivity... done.
The hardware layer is now available next to other layers inside the Poky reference repository on your build host as
meta-alteraand contains all the metadata needed to support hardware from Altera, which is owned by Intel.
It is recommended for layers to have a branch per Yocto Project release. Please make sure to checkout the layer branch supporting the Yocto Project release you’re using.
Change the Configuration to Build for a Specific Machine: The MACHINE variable in the
local.conffile specifies the machine for the build. For this example, set the MACHINE variable to
cyclone5. These configurations are used: https://github.com/kraj/meta-altera/blob/master/conf/machine/cyclone5.conf.
See the “Examine Your Local Configuration File” step earlier for more information on configuring the build.
Add Your Layer to the Layer Configuration File: Before you can use a layer during a build, you must add it to your
bblayers.conffile, which is found in the Build Directory
bitbake-layers add-layercommand to add the layer to the configuration file:
$ cd poky/build $ bitbake-layers add-layer ../meta-altera NOTE: Starting bitbake server... Parsing recipes: 100% |##################################################################| Time: 0:00:32 Parsing of 918 .bb files complete (0 cached, 918 parsed). 1401 targets, 123 skipped, 0 masked, 0 errors.
You can find more information on adding layers in the Adding a Layer Using the bitbake-layers Script section.
Completing these steps has added the
meta-altera layer to your Yocto
Project development environment and configured it to build for the
The previous steps are for demonstration purposes only. If you were
to attempt to build an image for the
cyclone5 machine, you should
read the Altera
Creating Your Own General Layer¶
Maybe you have an application or specific set of behaviors you need to
isolate. You can create your own general layer using the
bitbake-layers create-layer command. The tool automates layer
creation by setting up a subdirectory with a
configuration file, a
recipes-example subdirectory that contains an
example.bb recipe, a licensing file, and a
The following commands run the tool to create a layer named
meta-mylayer in the
$ cd poky $ bitbake-layers create-layer meta-mylayer NOTE: Starting bitbake server... Add your new layer with 'bitbake-layers add-layer meta-mylayer'
For more information on layers and how to create them, see the Creating a General Layer Using the bitbake-layers Script section in the Yocto Project Development Tasks Manual.
Where To Go Next¶
Now that you have experienced using the Yocto Project, you might be asking yourself “What now?”. The Yocto Project has many sources of information including the website, wiki pages, and user manuals:
Website: The Yocto Project Website provides background information, the latest builds, breaking news, full development documentation, and access to a rich Yocto Project Development Community into which you can tap.
Video Seminar: The Introduction to the Yocto Project and Bitbake, Part 1 and Introduction to the Yocto Project and Bitbake, Part 2 videos offer a video seminar introducing you to the most important aspects of developing a custom embedded Linux distribution with the Yocto Project.
Yocto Project Overview and Concepts Manual: The Yocto Project Overview and Concepts Manual is a great place to start to learn about the Yocto Project. This manual introduces you to the Yocto Project and its development environment. The manual also provides conceptual information for various aspects of the Yocto Project.
Yocto Project Wiki: The Yocto Project Wiki provides additional information on where to go next when ramping up with the Yocto Project, release information, project planning, and QA information.
Yocto Project Mailing Lists: Related mailing lists provide a forum for discussion, patch submission and announcements. There are several mailing lists grouped by topic. See the Mailing lists section in the Yocto Project Reference Manual for a complete list of Yocto Project mailing lists.
Comprehensive List of Links and Other Documentation: The Links and Related Documentation section in the Yocto Project Reference Manual provides a comprehensive list of all related links and other user documentation.
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