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diff --git a/documentation/ref-manual/release-process.rst b/documentation/ref-manual/release-process.rst new file mode 100644 index 0000000000..d8d362282b --- /dev/null +++ b/documentation/ref-manual/release-process.rst @@ -0,0 +1,191 @@ +.. SPDX-License-Identifier: CC-BY-SA-2.0-UK + +***************************************************** +Yocto Project Releases and the Stable Release Process +***************************************************** + +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. + +Major and Minor Release Cadence +=============================== + +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 "`Major Release +Codenames <#major-release-codenames>`__" section for information on +codenames used with major releases. + + - 2.2 (Morty) + - 2.1 (Krogoth) + - 2.0 (Jethro) + +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. + +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: + + - 2.1.1 + - 2.1.2 + - 2.2.1 + +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. + +Major Release Codenames +======================= + +Each major release receives a codename that identifies the release in +the :ref:`overview-manual/development-environment:yocto project source repositories`. +The concept is that branches of :term:`Metadata` 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. + +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 +:yocto_wiki:`/Releases`. + +Stable Release Process +====================== + +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. + +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 +:yocto_wiki:`/Stable_branch_maintenance`. + +Testing and Quality Assurance +============================= + +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 +":ref:`dev-manual/common-tasks:performing automated runtime testing`" +section in the Yocto Project Development Tasks Manual. + +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: + +- ``bitbake-selftest``: A standalone command that runs unit tests on + key pieces of BitBake and its fetchers. + +- :ref:`sanity.bbclass <ref-classes-sanity>`: This automatically + included class checks the build environment for missing tools (e.g. + ``gcc``) or common misconfigurations such as + :term:`MACHINE` set incorrectly. + +- :ref:`insane.bbclass <ref-classes-insane>`: 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. + +- :ref:`testimage.bbclass <ref-classes-testimage*>`: This class + performs runtime testing of images after they are built. The tests + are usually used with :doc:`QEMU </dev-manual/qemu>` + 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. + +- :ref:`ptest <dev-manual/common-tasks:testing packages with ptest>`: + 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. + +- ``oe-selftest``: Tests combination BitBake invocations. These tests + operate outside the OpenEmbedded build system itself. The + ``oe-selftest`` can run all tests by default or can run selected + tests or test suites. + + .. note:: + + Running ``oe-selftest`` requires host packages beyond the "Essential" + grouping. See the :ref:`ref-manual/system-requirements:required packages for the build host` + section for more information. + +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. + +The Yocto Project's main Autobuilder (&YOCTO_AB_URL;) +publicly tests each Yocto Project release's code in the +:term:`OpenEmbedded-Core (OE-Core)`, 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 ``poky-contrib`` repository (i.e. the +master-under-test branch) or in the "master-next" branch in the ``poky`` +repository. + +.. note:: + + You can find all these branches in the Yocto Project + Source Repositories + . + +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. + +Various features such as ``multilib``, sub architectures (e.g. ``x32``, +``poky-tiny``, ``musl``, ``no-x11`` and and so forth), +``bitbake-selftest``, and ``oe-selftest`` 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. + +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. |