[install-guide] describe service clients auth

Currently install guide incorrectly advises operators to configure
access for service users used by ironic-conductor in
[keystone_authtoken] section.

Such way of configuration was deprecated in Newton release, and using it
will result in a warning log message.

This patch changes the advised way of configuring service users to an
appropriate one using config sections corresponding to each service client
to be used, as well as proper options for keystoneauth plugins and
sessions instead of legacy options.

Change-Id: I96967682f18988d9e32f2ecfa7792aa0e653db3f
Closes-Bug: #1628842

install-guide/source/include/configure-ironic-conductor.rst

@@ -109,32 +109,79 @@ Configuring ironic-conductor service
    cleaning, see `CleaningNetworkSetup <http://docs.openstack.org/developer/ironic/deploy/cleaning.html>`_
    from the Ironic deploy guide.
 
-#. Configure the ironic-conductor service to use these credentials with the
-   Identity service. Ironic-conductor should use the same configuration as
-   ironic-api. Replace ``IDENTITY_IP`` with the IP of the Identity server,
-   and replace ``IRONIC_PASSWORD`` with the password you chose for the
-   ``ironic`` user in the Identity service:
+#. Configure credentials for accessing other OpenStack services.
+
+   In order to communicate with other OpenStack services, the Bare Metal
+   service needs to use service users to authenticate to the OpenStack
+   Identity service when making requests to other services.
+   These users' credentials have to be configured in each
+   configuration file section related to the corresponding service:
+
+   * ``[neutron]`` - to access the OpenStack Networking service
+   * ``[glance]`` - to access the OpenStack Image service
+   * ``[swift]`` - to access the OpenStack Object Storage service
+   * ``[inspector]`` - to access the OpenStack Bare Metal Introspection
+     service
+   * ``[service_catalog]`` - a special section holding credentials
+     the Bare Metal service will use to discover its own API URL endpoint
+     as registered in the OpenStack Identity service catalog.
+
+   For simplicity, you can use the same service user for all services.
+   For backward compatibility, this should be the same user configured
+   in the ``[keystone_authtoken]`` section for the ironic-api service
+   (see "Configuring ironic-api service").
+   However, this is not necessary, and you can create and configure separate
+   service users for each service.
+
+   Under the hood, Bare Metal service uses ``keystoneauth`` library
+   together with ``Authentication plugin`` and ``Session`` concepts
+   provided by it to instantiate service clients.
+   Please refer to `Keystoneauth documentation`_ for supported plugins,
+   their available options as well as Session-related options
+   for authentication and connection respectively.
+
+   In the example below, authentication information for user to access the
+   OpenStack Networking service is configured to use:
+
+   * HTTPS connection with specific CA SSL certificate when making requests
+   * the same service user as configured for ironic-api service
+   * dynamic ``password`` authentication plugin that will discover
+     appropriate version of Identity service API based on other
+     provided options
+
+     - replace ``IDENTITY_IP`` with the IP of the Identity server,
+       and replace ``IRONIC_PASSWORD`` with the password you chose for the
+       ``ironic`` user in the Identity service
+
 
    .. code-block:: ini
 
-      [keystone_authtoken]
+      [neutron]
 
-      # Complete public Identity API endpoint (string value)
-      auth_uri=http://IDENTITY_IP:5000/
+      # Authentication type to load (string value)
+      auth_type = password
 
-      # Complete admin Identity API endpoint. This should specify
-      # the unversioned root endpoint e.g. https://localhost:35357/
-      # (string value)
-      identity_uri=http://IDENTITY_IP:35357/
+      # Authentication URL (string value)
+      auth_url=https://IDENTITY_IP:5000/
 
-      # Service username. (string value)
-      admin_user=ironic
+      # Username (string value)
+      username=ironic
 
-      # Service account password. (string value)
-      admin_password=IRONIC_PASSWORD
+      # User's password (string value)
+      password=IRONIC_PASSWORD
 
-      # Service tenant name. (string value)
-      admin_tenant_name=service
+      # Project name to scope to (string value)
+      project_name=service
+
+      # Domain ID containing project (string value)
+      project_domain_id=default
+
+      # User's domain id (string value)
+      user_domain_id=default
+
+      # PEM encoded Certificate Authority to use when verifying
+      # HTTPs connections. (string value)
+      cafile=/opt/stack/data/ca-bundle.pem
 
 #. Make sure that ``qemu-img`` and ``iscsiadm`` (in the case of using iscsi-deploy driver)
    binaries are installed and prepare the host system as described at
@@ -150,3 +197,6 @@ Configuring ironic-conductor service
 
       Ubuntu:
         sudo service ironic-conductor restart
+
+
+.. _Keystoneauth documentation: http://docs.openstack.org/developer/keystoneauth/