Initial commit of terminology.rst

docs/terminology.rst

@@ -0,0 +1,52 @@
+.. _terminology:
+
+===========
+Terminology
+===========
+
+``vPoller Proxy``
+   ZeroMQ proxy which distributes tasks to and load balances client
+   requests. The application running the ``vPoller Proxy`` is
+   ``vpoller-proxy``.
+
+``vPoller Worker``
+   Worker application which processes tasks, such as discovery and
+   polling of vSphere object properties. The ``vPoller Worker``
+   receives new tasks for processing from the ``backend`` endpoint
+   of a ``vPoller Proxy``. The application running the
+   ``vPoller Worker`` is ``vpoller-worker``.
+
+``vPoller Client``
+   Client application used for sending task requests and receiving
+   of results. The ``vPoller Client`` sends task requests to the
+   ``frontend`` endpoint of a ``vPoller Proxy``. The application
+   running the ``vPoller Client`` is ``vpoller-client`` and
+   ``vpoller-cclient``, which is the client application written in C.
+
+``vSphere Agent``
+   The ``vSphere Agents`` are the ones that take care of establishing
+   connections to the vSphere hosts and perform discovery and polling
+   of vSphere objects. The ``vSphere Agents`` are running on the
+   ``vPoller Workers`` and a single ``vPoller Worker`` can have
+   as many ``vSphere Agents`` as you'd like. ``vSphere Agents`` are
+   configured and managed by the ``vconnector-cli`` tool.
+
+On the image below you can see how each vPoller component relates to
+the others.
+
+.. image:: images/vpoller.png
+
+Here is what happens when you send a client task request:
+
+1. A ``vPoller Client`` sends a task request to the
+   ``frontend`` endpoint of a ``vPoller Proxy``.
+2. Task request is received on the ``vPoller Proxy`` and is
+   dispatched to any connected ``vPoller Workers`` on the ``backend``
+   endpoint.
+3. The task request is received on the ``vPoller Worker`` and given
+   to a ``vSphere Agent`` which is taking care of the requested
+   vSphere host for processing the request through the VMware
+   vSphere API.
+4. The ``vSphere Agent`` returns any result from the operation to the
+   ``vPoller Worker`` which in turn sends the result through the
+   ``vPoller Proxy`` back to the client which requested the task.