[DOCS] Adding storage arch to install guide draft

Change-Id: I491e37176e2f4d4373c481bd5817d0863b416b5c
Implements: blueprint osa-install-guide-overhaul

doc/source/install-guide-revised-draft/overview-ref-arch.rst

@@ -1,14 +0,0 @@
-`Home <index.html>`_ OpenStack-Ansible Installation Guide
-
-======================
-Reference Architecture
-======================
-
-.. TODO
-   - Describe OSA community reference architectures that can be installed
-     using OSA
-   - Add deployment view diagrams
-
---------------
-
-.. include:: navigation.txt

doc/source/install-guide-revised-draft/overview-storage-arch.rst

@@ -0,0 +1,67 @@
+`Home <index.html>`_ OpenStack-Ansible Installation Guide
+
+====================
+Storage architecture
+====================
+
+OpenStack Ansible supports Block Storage (cinder) and Object Storage (swift).
+
+
+Block storage (cinder)
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. Suggestion: Document the location of the cinder-api service (containers on the infra hosts)
+.. Suggestion: Document the location of the cinder-volumes service
+
+.. important::
+
+   The actual Block Storage service is not handled by OpenStack Ansible. The
+   exception to this is the LVM backend storage on physical hosts.
+
+When using LVM, you have separate physical hosts with the volume groups
+that cinder volumes will use.
+For any other external cinder storage including Ceph, EMC, NAS, and NFS,
+set up a container inside one of the infra hosts.
+
+.. note::
+
+   ``cinder_volumes`` do not run in HA `active/active` mode.
+   This is not to be set up on multiple hosts. If you have multiple storage
+   backends, set up one per volumes container.
+   For more information: `https://specs.openstack.org/openstack/cinder-specs/specs/mitaka/cinder-volume-active-active-support.html>`_.
+
+
+Networking for Block Storage (cinder)
+-------------------------------------
+
+Configure ``cinder-api`` infra hosts with ``br-storage`` for storage requests
+and ``br-mgmt`` for API requests. ``cinder-volumes`` hosts require
+``br-storage``.
+
+
+Object Storage (swift)
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. Suggestion: Document the location of the swift-proxy hosts (containers on the infra hosts).
+.. Suggestion: Document the location of the swift account/object/container services (on separate physical hosts)
+
+Networking for Object Storage (swift)
+-------------------------------------
+
+Ensure the proxy hosts for swift are on ``br-mgmt`` and ``br-storage``.
+``br-storage`` handles the retrieval and upload of objects to the storage
+nodes. ``br-mgmt`` handles the API requests.
+
+Ensure storage hosts are on ``br-storage``. When using dedicated
+replication, also ensure storage hosts are on ``br-repl``.
+``br-storage`` handles the transfer of objects from the storage hosts to
+the proxy and vice-versa.
+``br-repl`` handles the replication of objects between storage hosts,
+and is not needed by the proxy containers.
+
+``br-repl`` is optional. Replication occurs over the ``br-storage``
+interface when there is no ``br-repl`` replication bridge.
+
+--------------
+
+.. include:: navigation.txt

doc/source/install-guide-revised-draft/overview.rst

@@ -8,8 +8,8 @@ Chapter 1. Overview
 
    overview-osa.rst
    overview-host-layout
-   overview-ref-arch.rst
    overview-network-arch.rst
+   overview-storage-arch.rst
    overview-requirements.rst
    overview-security.rst
    overview-workflow.rst