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| <chapter id='ref-release-process'> |
| <title>Yocto Project Releases and the Stable Release Process</title> |
| |
| <para> |
| The Yocto Project release process is predictable and consists of both |
| major and minor (point) releases. |
| This brief chapter provides information on how releases are named, their |
| life cycle, and their stability. |
| </para> |
| |
| <section id='major-and-minor-release-cadence'> |
| <title>Major and Minor Release Cadence</title> |
| |
| <para> |
| The Yocto Project delivers major releases (e.g. &DISTRO;) using a six |
| month cadence roughly timed each April and October of the year. |
| Following are examples of some major YP releases with their codenames |
| also shown. |
| See the |
| "<link linkend='major-release-codenames'>Major Release Codenames</link>" |
| section for information on codenames used with major releases. |
| <literallayout class='monospaced'> |
| 2.2 (Morty) |
| 2.1 (Krogoth) |
| 2.0 (Jethro) |
| </literallayout> |
| While the cadence is never perfect, this timescale facilitates |
| regular releases that have strong QA cycles while not overwhelming |
| users with too many new releases. |
| The cadence is predictable and avoids many major holidays in various |
| geographies. |
| </para> |
| |
| <para> |
| The Yocto project delivers minor (point) releases on an unscheduled |
| basis and are usually driven by the accumulation of enough significant |
| fixes or enhancements to the associated major release. |
| Following are some example past point releases: |
| <literallayout class='monospaced'> |
| 2.1.1 |
| 2.1.2 |
| 2.2.1 |
| </literallayout> |
| The point release indicates a point in the major release branch where |
| a full QA cycle and release process validates the content of the new |
| branch. |
| <note> |
| Realize that there can be patches merged onto the stable release |
| branches as and when they become available. |
| </note> |
| </para> |
| </section> |
| |
| <section id='major-release-codenames'> |
| <title>Major Release Codenames</title> |
| |
| <para> |
| Each major release receives a codename that identifies the release in |
| the |
| <ulink url='&YOCTO_DOCS_OM_URL;#yocto-project-repositories'>Yocto Project Source Repositories</ulink>. |
| The concept is that branches of |
| <link linkend='metadata'>Metadata</link> |
| with the same codename are likely to be compatible and thus |
| work together. |
| <note> |
| Codenames are associated with major releases because a Yocto |
| Project release number (e.g. &DISTRO;) could conflict with |
| a given layer or company versioning scheme. |
| Codenames are unique, interesting, and easily identifiable. |
| </note> |
| Releases are given a nominal release version as well but the codename |
| is used in repositories for this reason. |
| You can find information on Yocto Project releases and codenames at |
| <ulink url='https://wiki.yoctoproject.org/wiki/Releases'></ulink>. |
| </para> |
| </section> |
| |
| <section id='stable-release-process'> |
| <title>Stable Release Process</title> |
| |
| <para> |
| Once released, the release enters the stable release process at which |
| time a person is assigned as the maintainer for that stable release. |
| This maintainer monitors activity for the release by investigating |
| and handling nominated patches and backport activity. |
| Only fixes and enhancements that have first been applied on the |
| "master" branch (i.e. the current, in-development branch) are |
| considered for backporting to a stable release. |
| <note> |
| The current Yocto Project policy regarding backporting is to |
| consider bug fixes and security fixes only. |
| Policy dictates that features are not backported to a stable |
| release. |
| This policy means generic recipe version upgrades are unlikely to |
| be accepted for backporting. |
| The exception to this policy occurs when a strong reason exists |
| such as the fix happens to also be the preferred upstream approach. |
| </note> |
| </para> |
| |
| <para> |
| Stable release branches have strong maintenance for about a year after |
| their initial release. |
| Should significant issues be found for any release regardless of its |
| age, fixes could be backported to older releases. |
| For issues that are not backported given an older release, |
| Community LTS trees and branches exist where |
| community members share patches for older releases. |
| However, these types of patches do not go through the same release |
| process as do point releases. |
| You can find more information about stable branch maintenance at |
| <ulink url='https://wiki.yoctoproject.org/wiki/Stable_branch_maintenance'></ulink>. |
| </para> |
| </section> |
| |
| <section id='testing-and-quality-assurance'> |
| <title>Testing and Quality Assurance</title> |
| |
| <para> |
| Part of the Yocto Project development and release process is quality |
| assurance through the execution of test strategies. |
| Test strategies provide the Yocto Project team a way to ensure a |
| release is validated. |
| Additionally, because the test strategies are visible to you as a |
| developer, you can validate your projects. |
| This section overviews the available test infrastructure used in the |
| Yocto Project. |
| For information on how to run available tests on your projects, see the |
| "<ulink url='&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing'>Performing Automated Runtime Testing</ulink>" |
| section in the Yocto Project Development Tasks Manual. |
| </para> |
| |
| <para> |
| The QA/testing infrastructure is woven into the project to the point |
| where core developers take some of it for granted. |
| The infrastructure consists of the following pieces: |
| <itemizedlist> |
| <listitem><para> |
| <filename>bitbake-selftest</filename>: |
| A standalone command that runs unit tests on key pieces of |
| BitBake and its fetchers. |
| </para></listitem> |
| <listitem><para> |
| <link linkend='ref-classes-sanity'><filename>sanity.bbclass</filename></link>: |
| This automatically included class checks the build environment |
| for missing tools (e.g. <filename>gcc</filename>) or common |
| misconfigurations such as |
| <link linkend='var-MACHINE'><filename>MACHINE</filename></link> |
| set incorrectly. |
| </para></listitem> |
| <listitem><para> |
| <link linkend='ref-classes-insane'><filename>insane.bbclass</filename></link>: |
| This class checks the generated output from builds for sanity. |
| For example, if building for an ARM target, did the build |
| produce ARM binaries. |
| If, for example, the build produced PPC binaries then there |
| is a problem. |
| </para></listitem> |
| <listitem><para> |
| <link linkend='ref-classes-testimage*'><filename>testimage.bbclass</filename></link>: |
| This class performs runtime testing of images after they are |
| built. |
| The tests are usually used with |
| <ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-qemu'>QEMU</ulink> |
| to boot the images and check the combined runtime result |
| boot operation and functions. |
| However, the test can also use the IP address of a machine to |
| test. |
| </para></listitem> |
| <listitem><para> |
| <ulink url='&YOCTO_DOCS_DEV_URL;#testing-packages-with-ptest'><filename>ptest</filename></ulink>: |
| Runs tests against packages produced during the build for a |
| given piece of software. |
| The test allows the packages to be be run within a target |
| image. |
| </para></listitem> |
| <listitem><para> |
| <filename>oe-selftest</filename>: |
| Tests combination BitBake invocations. |
| These tests operate outside the OpenEmbedded build system |
| itself. |
| The <filename>oe-selftest</filename> can run all tests by |
| default or can run selected tests or test suites. |
| <note> |
| Running <filename>oe-selftest</filename> requires |
| host packages beyond the "Essential" grouping. |
| See the |
| "<link linkend='required-packages-for-the-host-development-system'>Required Packages for the Host Development System</link>" |
| section for more information. |
| </note> |
| </para></listitem> |
| </itemizedlist> |
| </para> |
| |
| <para> |
| Originally, much of this testing was done manually. |
| However, significant effort has been made to automate the tests so |
| that more people can use them and the Yocto Project development team |
| can run them faster and more efficiently. |
| </para> |
| |
| <para> |
| The Yocto Project's main Autobuilder |
| (<filename>autobuilder.yoctoproject.org</filename>) publicly tests |
| each Yocto Project release's code in the |
| <link linkend='oe-core'>OE-Core</link>, Poky, and BitBake |
| repositories. |
| The testing occurs for both the current state of the |
| "master" branch and also for submitted patches. |
| Testing for submitted patches usually occurs in the |
| "ross/mut" branch in the <filename>poky-contrib</filename> repository |
| (i.e. the master-under-test branch) or in the "master-next" branch |
| in the <filename>poky</filename> repository. |
| <note> |
| You can find all these branches in the Yocto Project |
| <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>. |
| </note> |
| Testing within these public branches ensures in a publicly visible way |
| that all of the main supposed architectures and recipes in OE-Core |
| successfully build and behave properly. |
| </para> |
| |
| <para> |
| Various features such as <filename>multilib</filename>, sub |
| architectures (e.g. <filename>x32</filename>, |
| <filename>poky-tiny</filename>, <filename>musl</filename>, |
| <filename>no-x11</filename> and and so forth), |
| <filename>bitbake-selftest</filename>, and |
| <filename>oe-selftest</filename> are tested as part of |
| the QA process of a release. |
| Complete testing and validation for a release takes the Autobuilder |
| workers several hours. |
| <note> |
| The Autobuilder workers are non-homogeneous, which means regular |
| testing across a variety of Linux distributions occurs. |
| The Autobuilder is limited to only testing QEMU-based setups and |
| not real hardware. |
| </note> |
| </para> |
| |
| <para> |
| Finally, in addition to the Autobuilder's tests, the Yocto Project |
| QA team also performs testing on a variety of platforms, which includes |
| actual hardware, to ensure expected results. |
| </para> |
| </section> |
| |
| </chapter> |
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