Merge "Document the policy for Tempest & its plugins release"
diff --git a/doc/source/index.rst b/doc/source/index.rst
index ab994d1..a72e783 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -80,6 +80,14 @@
    plugin
    plugin-registry
 
+Tempest & Plugins Compatible Version Policy
+-------------------------------------------
+
+.. toctree::
+   :maxdepth: 2
+
+   tempest_and_plugins_compatible_version_policy
+
 Library
 -------
 
@@ -104,4 +112,4 @@
   * :ref:`Tempest document search <search>`: Search the contents of this document.
 
 * `OpenStack wide search <https://docs.openstack.org>`_: Search the wider
-  set of OpenStack documentation, including forums.
\ No newline at end of file
+  set of OpenStack documentation, including forums.
diff --git a/doc/source/tempest_and_plugins_compatible_version_policy.rst b/doc/source/tempest_and_plugins_compatible_version_policy.rst
new file mode 100644
index 0000000..942b1bd
--- /dev/null
+++ b/doc/source/tempest_and_plugins_compatible_version_policy.rst
@@ -0,0 +1,54 @@
+Tempest and Plugins compatible version policy
+=============================================
+
+Tempest and its plugins are responsible for the integrated
+testing of OpenStack. These tools have two use cases:
+
+#. Testing upstream code at gate
+#. Testing Production Cloud
+
+Upstream code is tested by the master version of branchless Tempest & plugins
+for all supported stable branches in `Maintained phase`_.
+
+Production Cloud can be tested by using the compatible version or using
+master version. It depends on the testing strategy of cloud. To provide
+the compatible version of Tempest and its Plugins per OpenStack release,
+we started the coordinated release of all plugins and Tempest per OpenStack
+release.
+These versions are the first set of versions from Tempest and its Plugins to
+officially start the support of a particular OpenStack release. For example:
+OpenStack Train release first compatible versions `Tempest plugins version`_.
+
+Because of branchless nature of Tempest and its plugins, first version
+released during OpenStack release is not the last version to support that
+OpenStack release. This means the next (or master) versions can also be used
+for upstream testing as well as in production testing.
+
+Since the `Extended Maintenance policy`_ for stable branch, Tempest
+started releasing the ``end of support`` version once stable release
+is moved to EM state, which used to happen on EOL of stable release. This is
+the last compatible version of Tempest for the OpenStack release moved to EM.
+
+Because of branchless nature as explained above, we have a range of versions
+which can be considered a compatible version for particular OpenStack release.
+How we should release those versions is mentioned in the below table.
+
+ +-----------------------------+-----------------+------------------------------------+
+ | First compatible version -> | OpenStack 'XYZ' | <- Last compatible version         |
+ +=============================+=================+====================================+
+ |This is the latest version   |                 |This is the version released        |
+ |released when OpenStack      |                 |when OpenStack 'XYZ' is moved to    |
+ |'XYZ' is released.           |                 |EM state. Hash used for this should |
+ |Example:                     |                 |be the hash from master at the time |
+ |`Tempest plugins version`_   |                 |of branch is EM not the one used for|
+ |                             |                 |First compatible version            |
+ +-----------------------------+-----------------+------------------------------------+
+
+Tempest & the Plugins should follow the above mentioned policy for the
+``First compatible version`` and the ``Last compatible version.``
+so that we provide the right set of compatible versions to Upstream as well as to
+Production Cloud testing.
+
+.. _Maintained phase: https://docs.openstack.org/project-team-guide/stable-branches.html#maintained
+.. _Extended Maintenance policy: https://governance.openstack.org/tc/resolutions/20180301-stable-branch-eol.html
+.. _Tempest plugins version: https://releases.openstack.org/train/#tempest-plugins