Add introduction block

Change-Id: Iccf0d2b2ff025488c40aa156590dc805e93dadd3

doc/source/index.rst

@@ -1,10 +1,24 @@
 Performance Documentation
 *************************
 
+Abstract
+========
+
+This documentation section aims to introduce ideas and best practices on how
+OpenStack cloud may be exercised to evaluate its performance, what can be
+called performance at all and how it can be measured. Here you will find both
+testing/probing methodologies and test plans, proposed by OpenStack community
+members (as well as results of their execution against various cloud
+topologies).
+
+Contents
+========
+
 .. toctree::
     :numbered:
-    :maxdepth: 3
+    :maxdepth: 2
 
+    introduction.rst
     methodologies/index.rst
     test_plans/index.rst
 

doc/source/introduction.rst

@@ -0,0 +1,44 @@
+Introduction
+============
+
+What is the reason for writing this?
+------------------------------------
+
+Cloud computing is a complex and evolving process. Its definition can be as
+simple as:
+
+    **a style of computing in which scalable and elastic IT-enabled
+    capabilities are delivered as a service using Internet technologies**
+    (*IT Glossary: Cloud Computing*)
+
+At the same time it may require a separate article to explain what cloud
+computing is. There are several characteristics which can describe the system,
+called *cloud*: on **demand**, **scale**, **elasticity**, and **as a Service**.
+All these characteristics are areas of interest for scale and performance
+testing.
+
+All documentation pieces you'll find here are the summary of knowledge and
+experience gained by various people from different companies, that aims to
+share the ideas of how we can evaluate, analyse and test OpenStack cloud
+performance, including the very infrastructure basics.
+
+As a community we want this knowledge to become publicly available to allow
+OpenStack developers, QA engineers and operators to have unified way for their
+projects and products evaluation and best recipes for doing this.
+
+Who will be interested in this?
+-------------------------------
+
+Cloud operators, software and quality assurance engineers and any person who
+takes active part in either OpenStack development or its usage.
+
+Who is contributing to this guide?
+----------------------------------
+
+Short answer: OpenStack community.
+
+A bit longer answer: performance engineers from various companies, cloud
+operators, OpenStack projects developers, etc. We all are part of
+**Performance Team**. Therefore you can find here
+test plans and methodologies, that were written keeping in mind all these
+groups of people, their interest and experience.