Add configuration document for Unity manila driver

Add configuration document for Unity manila driver which is new
added in the newton release.

Change-Id: I906c85cae17101c8a08353da58bb1e645b2fc479
Closes-Bug: #1628373

doc/config-reference/source/shared-file-systems/drivers.rst

@@ -16,6 +16,7 @@ Share drivers
    drivers/zfs-on-linux-driver.rst
    drivers/emc-isilon-driver.rst
    drivers/emc-vnx-driver.rst
+   drivers/emc-unity-driver.rst
    drivers/hitachi-hnas-driver.rst
    drivers/hpe-3par-share-driver.rst
    drivers/huawei-nas-driver.rst

doc/config-reference/source/shared-file-systems/drivers/emc-unity-driver.rst

@@ -0,0 +1,182 @@
+================
+EMC Unity driver
+================
+
+The EMC Shared File Systems service driver framework (EMCShareDriver)
+utilizes the EMC storage products to provide the shared file systems to
+OpenStack. The EMC driver is a plug-in based driver which is designed to
+use different plug-ins to manage different EMC storage products.
+
+The Unity plug-in manages the Unity system to provide shared filesystems.
+The EMC driver framework with the Unity plug-in is referred to as the
+Unity driver in this document.
+
+This driver performs the operations on Unity through RESTful APIs. Each back
+end manages one Storage Processor of Unity. Configure multiple Shared File
+Systems service back ends to manage multiple Unity systems.
+
+Requirements
+~~~~~~~~~~~~
+
+- Unity OE 4.0.1 or higher.
+
+- StorOps 0.2.17 or higher is installed on Manila node.
+
+- Following licenses are activated on Unity:
+
+  - CIFS/SMB Support
+
+  - Network File System (NFS)
+
+  - Thin Provisioning
+
+
+Supported shared filesystems and operations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The driver supports CIFS and NFS shares.
+
+The following operations are supported:
+
+-  Create a share.
+
+-  Delete a share.
+
+-  Allow share access.
+
+   Note the following limitations:
+
+   -  Only IP access type is supported for NFS.
+   -  Only user access type is supported for CIFS.
+
+-  Deny share access.
+
+-  Create a snapshot.
+
+-  Delete a snapshot.
+
+-  Create a share from a snapshot.
+
+-  Extend a share.
+
+
+Supported network types
+~~~~~~~~~~~~~~~~~~~~~~~
+
+- Flat
+
+- VLAN
+
+
+Pre-configurations
+~~~~~~~~~~~~~~~~~~
+
+On manila node
+--------------
+
+Python library ``storops`` is required to run Unity driver.
+Install it with the ``pip`` command.
+You may need root privilege to install python libraries.
+
+.. code-block:: console
+
+    pip install storops
+
+
+On Unity system
+---------------
+
+#. Configure system level NTP server.
+
+   Open ``Unisphere`` of your Unity system and navigate to:
+
+   .. code-block:: console
+
+      Unisphere -> Settings -> Management -> System Time and NTP
+
+   Select ``Enable NTP synchronization`` and add your NTP server(s).
+
+   The time on the Unity system and the Active Directory domains
+   used in security services should be in sync. We recommend
+   using the same NTP server on both the Unity system and Active
+   Directory domains.
+
+#. Configure system level DNS server.
+
+   Open ``Unisphere`` of your Unity system and navigate to:
+
+   .. code-block:: console
+
+      Unisphere -> Settings -> Management -> DNS Server
+
+   Select ``Configure DNS server address manually`` and add your DNS server(s).
+
+
+Back end configurations
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Following configurations need to be configured in ``/etc/manila/manila.conf``
+for the Unity driver.
+
+.. code-block:: ini
+
+    share_driver = manila.share.drivers.emc.driver.EMCShareDriver
+    emc_share_backend = unity
+    emc_nas_server = <management IP address of the Unity system>
+    emc_nas_login = <user with administrator privilege>
+    emc_nas_password = <password>
+    emc_nas_server_container = [SPA|SPB]
+    emc_nas_pool_names = <Comma separated pool names>
+    emc_interface_ports = <Comma separated ports list>
+
+- ``emc_share_backend``
+    The plugin name. Set it to `unity` for the Unity driver.
+
+- ``emc_nas_server``
+    The management IP for Unity.
+
+- ``emc_nas_server_container``
+    The SP to be used as share server.
+
+- ``emc_nas_pool_names``
+    Comma separated list specifying the name of the pools to be used
+    by this back end. Do not set this option if all storage pools
+    on the system can be used.
+    Wild card character is supported.
+
+    Examples: pool_1, pool_*, *
+
+- ``emc_interface_ports``
+    Comma separated list specifying the ethernet ports of Unity system
+    that can be used for share. Do not set this option if all ethernet ports
+    can be used.
+    Wild card character is supported.
+
+    Examples: spa_eth1, spa_*, *
+
+Restart of :term:`manila-share` service is needed for the configuration
+changes to take effect.
+
+
+Restrictions
+~~~~~~~~~~~~
+
+The Unity driver has following restrictions.
+
+- EMC Unity does not support the same IP in different VLANs.
+
+- Only IP access type is supported for NFS.
+
+- Only user access type is supported for CIFS.
+
+- Only Active Directory security service is supported and it is
+  required to create CIFS shares.
+
+- Only one security service can be configured for each share network.
+
+
+Driver options
+~~~~~~~~~~~~~~
+
+Configuration options specific to this driver are documented in
+:ref:`manila-emc`.