Add Keycloak authentication doc for server side

TODO:
* Add info into client side auth section

Partially implements: blueprint mistral-keycloak-auth-docs

Change-Id: I930d5773ca2607bbe99fb22a17c39eda94ca34d5

doc/source/guides/configuration_guide.rst

@@ -7,13 +7,13 @@ either with real OpenStack environment or without OpenStack environment.
 **NOTE:** The most of the following operations should performed in mistral
 directory.
 
-1. Generate *mistral.conf* (if it does not already exist)::
+#. Generate *mistral.conf* (if it does not already exist)::
 
     $ oslo-config-generator --config-file tools/config/config-generator.mistral.conf --output-file /etc/mistral/mistral.conf
 
-2. Edit file **/etc/mistral/mistral.conf**.
+#. Edit file **/etc/mistral/mistral.conf**.
 
-3. **If you are not using OpenStack, skip this item.** Provide valid keystone
+#. **If you are not using OpenStack, skip this item.** Provide valid keystone
    auth properties::
 
     [keystone_authtoken]
@@ -24,7 +24,19 @@ directory.
     admin_password = <password>
     admin_tenant_name = <tenant>
 
-4. If you want to configure SSL for Mistral API server, provide following options
+#. Mistral can be also configured to authenticate with Keycloak server via OpenID Connect protocol.
+   In order to enable Keycloak authentication the following section should be in the config file::
+
+    auth_type = keycloak-oidc
+
+    [keycloak_oidc]
+    auth_url = https://<Keycloak-server-host>:<Keycloak-server-port>/auth
+
+   Property 'auth_type' is assigned to 'keystone' by default.
+   If SSL/TLS verification needs to be disabled then 'insecure = True' should also be added
+   under [keycloak_oidc] group.
+
+#. If you want to configure SSL for Mistral API server, provide following options
    in config file::
 
     [api]
@@ -35,20 +47,20 @@ directory.
     cert_file = <path-to-certificate file>
     key_file = <path-to-key file>
 
-5. **If you don't use OpenStack or you want to disable authentication for the
+#. **If you don't use OpenStack or you want to disable authentication for the
    Mistral service**, provide ``auth_enable = False`` in the config file::
 
     [pecan]
     auth_enable = False
 
-6. **If you are not using OpenStack, skip this item**. Register Mistral service
+#. **If you are not using OpenStack, skip this item**. Register Mistral service
    and Mistral endpoints on Keystone::
 
     $ MISTRAL_URL="http://[host]:[port]/v2"
     $ openstack service create workflow --name mistral --description 'OpenStack Workflow service'
     $ openstack endpoint create workflow --publicurl $MISTRAL_URL --adminurl $MISTRAL_URL --internalurl $MISTRAL_URL
 
-7. Configure transport properties in the corresponding config section: for
+#. Configure transport properties in the corresponding config section: for
    RabbitMQ it is **oslo_messaging_rabbit**::
 
     [oslo_messaging_rabbit]
@@ -56,16 +68,15 @@ directory.
     rabbit_password = <password>
     rabbit_host = <host>
 
- **NOTE**: Make sure that backend transport configuration is correct. Example for
- RabbitMQ::
+   **NOTE**: Make sure that backend transport configuration is correct. Example for RabbitMQ::
 
     [DEFAULT]
     rpc_backend = rabbit
 
-8. Configure database. **SQLite can't be used in production**. Use *MySQL* or
+#. Configure database. **SQLite can't be used in production**. Use *MySQL* or
    *PostgreSQL* instead. Here are the steps how to connect *MySQL* DB to Mistral:
 
- Make sure you have installed **mysql-server** package on your Database machine
+   Make sure you have installed **mysql-server** package on your database machine
    (it can be your Mistral machine as well).
 
    Install MySQL driver for python::
@@ -89,13 +100,13 @@ directory.
 
     connection = postgresql://<user>:<password>@<database-host>:5432/mistral
 
-9. **If you are not using OpenStack, skip this item.**
+#. **If you are not using OpenStack, skip this item.**
    Update mistral/actions/openstack/mapping.json file which contains all allowed
    OpenStack actions, according to the specific client versions of OpenStack
    projects in your deployment. Please find more detailed information in
    tools/get_action_list.py script.
 
-10. Configure Task affinity feature if needed. It is needed for distinguishing
+#. Configure Task affinity feature if needed. It is needed for distinguishing
    either single task executor or one task executor from group of task executors::
 
     [executor]
@@ -111,14 +122,14 @@ directory.
       target: my_favorite_executor
     ...Workflow YAML...
 
-11. Configure role based access policies for Mistral endpoints (policy.json)::
+#. Configure role based access policies for Mistral endpoints (policy.json)::
 
      [oslo_policy]
      policy_file = <path-of-policy.json file>
 
     Default policy.json file is in ``mistral/etc/``. For more deatils see `policy.json file <http://docs.openstack.org/mitaka/config-reference/policy-json-file.html>`_.
 
-12. After that try to run mistral engine and see it is running without any error::
+#. After that try to run mistral engine and see it is running without any error::
 
      $ mistral-server --config-file <path-to-config> --server engine