Policies

Policies

Revision: 6 Published: 2022-05-06

OpenEmbedded Release Series Support

In order to keep the number of combinations of DISTRO-s, ROS distros, and OpenEmbedded release series for which we do builds to a reasonable value, our support policy for OpenEmbedded release series is as follows:

1. When a new ROS distro is first released, build/files/ros[12]-<ROS-DISTRO>-*.mcf are created for the (typically two) OpenEmbedded release series that have a Support Level of Stable or Long Term Support as shown on Yocto Releases.
2. When an OpenEmbedded release series moves from the Dev to the Stable or Long Term Support Support Level, a new release series moves to Dev and build/files/ros[12]-*-<NEW-DEV-OE-RELEASE-SERIES>.mcf are created for all ROS distro-s that are current. However, the creation of the *.mcf files is deferred until there is a commit in a OpenEmbedded master branch that is unique to the new release series.
3. When an OpenEmbedded release series moves to the Community Support Level, build/files/ros[12]-*-<OE-RELEASE-SERIES>.mcf are moved to build/files-unsupported and builds are no longer done using them, except those for ROS distro-s which are LTS, eg, foxy or melodic, where this is done when the OpenEmbedded release series moves to the EOL Support Level. However, even those for these ROS distro-s are not guaranteed to be updated for newer releases of the ROS distro-s nor for upstream changes to the OpenEmbedded release series, and only "best efforts" will be made to keep them buildable.
4. The OpenEmbedded release series used by the build of webOS OSE currently being used is always supported, even if it no longer has a Support Level of Stable or Long Term Support, ie, build/files/{webos,ros[12]}-*-<WEBOS-OE-RELEASE-SERIES>.mcf always exist. When webOS OSE moves to a new OpenEmbedded release series, if its previous OpenEmbedded release series does not have a Support Level of Stable or Long Term Support, build/files/{webos,ros[12]}-*-<WEBOS-OE-RELEASE-SERIES>.mcf are moved to build/files-unsupported and builds are no longer done using them, except those for ROS distro-s which are LTS, eg, foxy or melodic, where this is done when the OpenEmbedded release series moves to the EOL Support Level.
5. When a ROS distro reaches its EOL and keeping it building successfully becames non-trivial because of on-going updates to the OpenEmbedded release series, its meta-ros[12]-<ROS-DISTRO> sublayer is dropped, its build/files/{webos,ros[12]}-<ROS-DISTRO>-*.mcfare moved to build/files-unsupported, and builds are no longer done using them.
6. There will always be at least one build/files/{webos,ros[12]}-<ROS-DISTRO>-<OE-RELEASE-SERIES>.mcf for every non-EOL ROS distro. However, the value(s) of <OE-RELEASE-SERIES> will change during the lifetime of a ROS distro.

SupportLevel Values in *.mcf Files

As of Milestone 17, each build/files*/{webos,ros[12]}-<ROS-DISTRO>-<OE-RELEASE-SERIES>.mcf contains a SupportLevel variable with one of four possible values:

Value	Definition
full	the configuration is fully supported
best-effort	the configuration has an EOL-ed ROS distro or OpenEmbedded release series, which means only a "best effort" will be made to have all its packages build
unsupported	the configuration is never built and only updated to fix breaking changes introduced upstream, eg, [master] of a component's repository being renamed to [main] or git:// needing to be replaced by https://
contrib	the configuration has been contributed and is not built

MACHINE Support

As of Milestone 11, meta-ros supports building for OpenEmbedded release series newer than thud and has migrated to webOS OSE version 2.x . This means that meta-ros could be built for Raspberry Pi 4, 64-bit and 32-bit, as well as Raspberry Pi 3. In order to reduce the number of combinations for which we do builds, the policy is that we will do them for one variant of QEMU and one variant of Raspberry Pi for each OpenEmbedded release series based on the DISTRO as per the table below (updated for Milestone 17). However, we won't do anything that knowing prevents others from building for the other variants.

OpenEmbedded Release Series | DISTRO:	ros1	ros2	webos
dunfell	qemux86, raspberrypi4	qemux86, raspberrypi4	qemux86-64, raspberrypi4-64
gatesgarth	qemux86, raspberrypi4	qemux86, raspberrypi4	N/A
hardknott	qemux86, raspberrypi4	qemux86, raspberrypi4	N/A
honister	qemux86, raspberrypi4	qemux86, raspberrypi4	N/A
kirkstone	qemux86, raspberrypi4	qemux86, raspberrypi4	N/A

Rationale: As of v2.14.0, upstream webOS OSE has been focused on qemux86-64 and raspberrypi4-64, which means the 32-bit variants aren't regularly tested and often are broken. Because webOS OSE is built with both ROS 1 and ROS 2 distros, building DISTRO = ros1 and DISTRO = ros2 for the 32-bit variants ensures that ROS packages of both versions have build coverage for all four architectures.

Note that ROS 1 package that supports the Raspberry Pi camera (raspicam-node) can not be built for 64-bit.

Baseline Platform and Selection of Platform Package Versions

The term baseline platform is defined to be the value of distribution_file.release_platforms from <ROS_DISTRO>-cache.yaml chosen as the platform release to which the OpenEmbedded metadata for a ROS distro is targeted. Our policy is to chose the Ubuntu release when there is more than one specified.

The packages provided by the baseline platform are known as platform packages. As of Milestone 12, our policy for selecting which version of a platform package to provide changed from trying to match that provided by the baseline platform to using the default version provided by the OpenEmbedded release series being used. We will attempt to create patches for ROS packages to allow them to build with the versions provided, but when this isn't possible, eg, a ROS 2 foxy package requiring a version of a platform package that is not supplied by thud, their recipes will be blacklisted.

Note that webOS OSE sets PREFERRED_VERSION_* for various platform packages to the versions it requires.

When importing a recipe from another OpenEmbedded layer or creating a new recipe, the latest version available at the time of import or creation used, unless the ROS package(s) that are dependent on it require a different one in order to build.

Miscellaneous

• The commits to which the upstream OpenEmbedded layers in build/files/webos-*-<OE-RELEASE-SERIES>.mcf are pinned will match those from which the supported release of webOS OSE are built. The ones in build/files/ros[12]-*-<OE-RELEASE-SERIES>.mcf will not be constrained by this and will the track the latest available from the upstream OpenEmbedded layers.

Change Log

Revision 6

• Update the MACHINE Support section for the kirkstone OpenEmbedded release series supported in Milestone 17. Also update it for DISTRO = ros2 being built for 32-bit architectures instead of 64-bit ones and for DISTRO = webos being built for 64-bit architectures instead of 32-bit ones.
• Clarify when the *.mcf files are created for a new OpenEmbedded release series.
• dashing is EOL, so use foxy as the example of an LTS ROS 2 distro.
• Add a SupportLevel Values in *.mcf Files section.

Revision 5

• Update the MACHINE Support section for the changes to the OpenEmbedded release series supported in Milestone 16:
  • Drop thud, warrior, zeus. This means we are no longer doing builds for raspberrypi3.
  • Add gatesgarth, hardknott, and honister.
• Clarify when support for an EOL ROS distro is dropped.

Revision 4

• Update for the introduction of a Long Term Support Yocto Support Level.
• Reduce the level of support given for the use of OpenEmbedded release series at Community Support Level with ROS distro-s which are LTS.
• Clarify that only build/files/webos-*-<OE-RELEASE-SERIES>.mcf are constrained to use the same commits of upstream OpenEmbedded layers as webOS OSE.

Revision 3

• Update Baseline Platform and Selection of Platform Package Versions section with the policy for imported and new recipes.

Revision 2

• Add items to the OpenEmbedded Release Series Support section:
  • for the policy when new OpenEmbedded release series are released;
  • to clarify that every non-EOL ROS distro will always be supported by least one stable OpenEmbedded release series.
• Clarify for which OpenEmbedded release series *.mcf files are created when a release series moves from the Dev to the Stable Support Level.
• Instead of dropping *.mcf files for unsupported cases, move them to a new build/files-unsupported directory and state that builds are no longer done for them.
• Clarify the policy when an OpenEmbedded release series moves to the EOL Support Level.
• Prefix all of the *.mcf with build/files/ so that there's no confusion with the existing ones under build/files-contrib and the new build/files-unsupported.
• Add a Baseline Platform and Selection of Platform Package Versions section.

Revision 1

• Initial publication.