A Practical Introduction to Yocto Project
This tutorial aims to get you started on Yocto development. The final goal is to build and emulate a minimal x86-64 GNU/Linux environment with qemu.
The Yocto Project is a collaborative umbrella project coordinated by the Linux Foundation. Its main goal is to help developers create custom GNU/Linux-based Distributions for multiple hardware architectures.
Yocto's main components are BitBake, OpenEmbedded, and Poky.
BitBake is a python based make-like build tool specialized in cross compilation, although not limited to that. BitBake is inspired by Portage, Gentoo's package management system. BitBake uses recipes, which are metadata files with information about the packages to be built.
OpenEmbedded is a cross-compilation and build-automation framework focused on creating Linux distributions for embedded devices, adopted by the Yocto Project in 2011. OpenEmbedded modularizes BitBake recipes in form of layers. Each layer is called
meta-layername.Poky is the reference distribution of the Yocto Project. It contains the OpenEmbedded Build System (BitBake and OpenEmbedded Core) as well as a set of metadata to get you started building your own distro.
For more information, refer to the Yocto Project Mega Manual. Yocto is famous for its solid documentation. You can find a neat "getting started" style section here, which is where this tutorial is based off of.
Minimal requirements:
- x86-64 CPU with at least 4 cores
- Ubuntu 16.04.4 LTS (Xenial Xerus)
- at least 50GB of space at $HOME
Install Yocto dependencies:
$ sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat cpio python python3 python3-pip python3-pexpect xz-utils debianutils iputils-ping libsdl1.2-dev xterm
Clone Poky
$ cd ~
$ git clone git://git.yoctoproject.org/poky
Start build environment
cd poky
source oe-init-build-env build
Edit conf/local.conf
- MACHINE ??= "qemux86-64"
- DL_DIR ?= "${TOPDIR}/downloads"
- PARALLEL_MAKE = "-j4"
- BB_NUMBER_THREADS = "12"
Obs.: the optimal number of parallel make and BitBake tasks might vary, depending on your host hardware.
Start BitBake
bitbake core-image-minimal
Obs.: this step might take from a few to several hours, depending on your host hardware.
Start QEMU
runqemu qemux86-64 core-image-minimal nographic
Obs.: the nographic option is only required if you're accessing the build host remotely. If you're on a desktop environment, feel free to remove this option and watch QEMU emulate the video output.
This tutorial is brought to you by EosBake.
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