7. DPDK Stable Releases and Long Term Support

This section sets out the guidelines for the DPDK Stable Releases and the DPDK Long Term Support releases (LTS).

7.1. Introduction

The purpose of the DPDK Stable Releases is to maintain releases of DPDK with backported fixes over an extended period of time. This provides downstream consumers of DPDK with a stable target on which to base applications or packages.

The Long Term Support release (LTS) is a designation applied to a Stable Release to indicate longer term support.

7.2. Stable Releases

Any major release of DPDK can be designated as a Stable Release if a maintainer volunteers to maintain it and there is a commitment from major contributors to validate it before releases. If a release is to be designated as a Stable Release, it should be done by 1 month after the master release.

A Stable Release is used to backport fixes from an N release back to an N-1 release, for example, from 16.11 to 16.07.

The duration of a stable is one complete release cycle (3 months). It can be longer, up to 1 year, if a maintainer continues to support the stable branch, or if users supply backported fixes, however the explicit commitment should be for one release cycle.

The release cadence is determined by the maintainer based on the number of bugfixes and the criticality of the bugs. Releases should be coordinated with the validation engineers to ensure that a tagged release has been tested.

7.3. LTS Release

A stable release can be designated as an LTS release based on community agreement and a commitment from a maintainer. The current policy is that each year’s November (X.11) release will be maintained as an LTS for 2 years.

After the X.11 release, an LTS branch will be created for it at http://git.dpdk.org/dpdk-stable where bugfixes will be backported to.

It is anticipated that there will be at least 4 releases per year of the LTS or approximately 1 every 3 months. However, the cadence can be shorter or longer depending on the number and criticality of the backported fixes. Releases should be coordinated with the validation engineers to ensure that a tagged release has been tested.

The current maintained LTS branches are 17.11 and 18.11.

At the end of the 2 years, a final X.11.N release will be made and at that point the LTS branch will no longer be maintained with no further releases.

7.4. What changes should be backported

Backporting should be limited to bug fixes. All patches accepted on the master branch with a Fixes: tag should be backported to the relevant stable/LTS branches, unless the submitter indicates otherwise. If there are exceptions, they will be discussed on the mailing lists.

Fixes suitable for backport should have a Cc: stable@dpdk.org tag in the commit message body as follows:

doc: fix some parameter description

Update the docs, fixing description of some parameter.

Fixes: abcdefgh1234 ("doc: add some parameter")
Cc: stable@dpdk.org

Signed-off-by: Alex Smith <alex.smith@example.com>

Fixes not suitable for backport should not include the Cc: stable@dpdk.org tag.

Features should not be backported to stable releases. It may be acceptable, in limited cases, to back port features for the LTS release where:

  • There is a justifiable use case (for example a new PMD).
  • The change is non-invasive.
  • The work of preparing the backport is done by the proposer.
  • There is support within the community.

7.5. The Stable Mailing List

The Stable and LTS release are coordinated on the stable@dpdk.org mailing list.

All fix patches to the master branch that are candidates for backporting should also be CCed to the stable@dpdk.org mailing list.

7.6. Releasing

A Stable Release will be released by:

  • Tagging the release with YY.MM.n (year, month, number).
  • Uploading a tarball of the release to dpdk.org.
  • Sending an announcement to the announce@dpdk.org list.

Stable releases are available on the dpdk.org download page.

7.7. ABI

The Stable Release should not be seen as a way of breaking or circumventing the DPDK ABI policy.