Initial commit for meteos documentation

Added the architecture document for meteos.

Change-Id: I83018975a2f5b1b318eb643dd78cc05d3f9d6bf9
Partial-Implements: blueprint meteos-docs

doc/source/architecture.rst

@@ -0,0 +1,32 @@
+Meteos Architecture
+===================
+
+Meteos is Machine Learning as a Service (MLaaS) in Apache Spark. Meteos create
+a workspace of Machine Learning via sahara spark plugin and manage some
+resources and jobs regarding Machine Learning.
+
+Meteos components
+~~~~~~~~~~~~~~~~~
+
+Meteos consist of meteos-api service and meteos-engine service.
+
+* meteos-api - web service which has REST interface.
+* meteos-engine - service which manage Meteos resources.
+
+Resources
+~~~~~~~~~
+
+Meteos manages these resources regarding machine learning.
+
+* Experiment Template - Template which define experiment like number of
+  master/worker nodes, spark version, base VM image, flavor, network, etc.
+* Experiment - a workspace of Machine Learning.
+* Data Set - a data parsed by user to create a Prediction Model.
+* Prediction Model - a model produced by data mining and machine learning
+  algorithms.
+* Learning Job - a job which consists of input data, output data(predicted
+  data), job status, job stdout/stderr.
+
+The following diagram illustrates the architecture of mistral:
+
+.. image:: img/Meteos-architecture.png

doc/source/index.rst

@@ -41,6 +41,7 @@ Developer Docs
 .. toctree::
    :maxdepth: 1
 
+   architecture
    devref/index
    man/index
    api/autoindex