Add spec for the plugin

Since the plugin is already developed, the spec just outlines
the way it was done.

Change-Id: Id5e79106893b6ffc803d9eb327e2f21b9aee70aa

specs/detach-rabbitmq-plugin.rst

@@ -0,0 +1,123 @@
+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+===================================================
+Detach RabbitMQ Plugin for Fuel
+===================================================
+
+Problem description
+===================
+
+Fuel deploys RabbitMQ on Controller nodes along with MySQL and many OpenStack
+processes. Cloud operators need a way to deploy RabbitMQ on separate nodes, so
+that it does not fight for system resources with other processes.
+
+Proposed change
+===============
+
+Implement a Fuel plugin which deploys RabbitMQ on separate nodes. Plugin
+should introduce a new role - RabbitMQ. RabbitMQ should be installed only on
+machines marked with that new role.
+
+RabbitMQ should be managed by Pacemaker, just like it is now. To simplify
+plugin development, Controller and RabbitMQ nodes should not be compatible.
+That way we will be able to create two separate Pacemaker clusters: one for
+Controller nodes, and another for RabbitMQ ones.
+
+Alternatives
+------------
+
+It also might be implemented as Fuel core functionality.
+
+Data model impact
+-----------------
+
+None
+
+REST API impact
+---------------
+
+None
+
+Upgrade impact
+--------------
+
+Fuel currently supports upgrading of Fuel Master node, so it is necessary to
+install a new version of plugin which supports new Fuel release. For now it
+is not guaranteed that new versions of the plugin will support environments
+deployed by the old version.
+
+Security impact
+---------------
+
+None
+
+Notifications impact
+--------------------
+
+None
+
+Other end user impact
+---------------------
+
+Detach RabbitMQ plugin uses Fuel pluggable architecture. After it is
+installed, the user can enable the plugin on the Settings tab of the Fuel
+web UI.
+
+Performance Impact
+------------------
+
+Deploying RabbitMQ on separate nodes increases RabbitMQ stability and
+throughput.
+
+Other deployer impact
+---------------------
+
+None
+
+Developer impact
+----------------
+
+None
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+- Alex Schultz <aschultz@mirantis.com> - developer
+- Bartłomiej Piotrowski <bpiotrowski@mirantis.com> - developer
+
+Work Items
+----------
+
+* Create Fuel plugin bundle, which contains deployments scripts, puppet
+  modules and metadata
+* Test Detach RabbitMQ plugin
+* Create Documentation
+
+
+Dependencies
+============
+
+* Fuel 8.0
+
+Testing
+=======
+
+* Prepare a test plan
+* Test the plugin by deploying environments with all Fuel deployment modes
+
+Documentation Impact
+====================
+
+* Deployment Guide
+* User Guide (which features the plugin provides, how to use them in the
+  deployed OpenStack environment)
+* Test Plan
+* Test Report
+