docs: add link to OSA deployment guide for adding a role

Provide a direct reference to the OpenStack-Ansible deploy guide, helping users understand how to integrate a new role into their deployment.

Change-Id: I8dc9cb76649e897e0b544504981a4d2949b6dedd
Signed-off-by: Dmitriy Chubinidze <dcu995@gmail.com>

doc/source/index.rst

@@ -18,7 +18,7 @@ The DNS servers Designate will interface with can be defined in the
 file.
 
 To clone or view the source code for this repository, visit the role repository
-for `os_designate <https://github.com/openstack/openstack-ansible-os_designate>`_.
+for `os_designate <https://opendev.org/openstack/openstack-ansible-os_designate>`_.
 
 Default variables
 ~~~~~~~~~~~~~~~~~
@@ -27,11 +27,46 @@ Default variables
    :language: yaml
    :start-after: under the License.
 
+Adding The Service to Your OpenStack-Ansible Deployment
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To add a new service to your OpenStack-Ansible (OSA) deployment:
+
+* Define ``designate_pools_yaml`` variable as described above.
+
+* Define ``dnsaas_hosts`` in your ``conf.d`` or ``openstack_user_config.yml``.
+  For example:
+
+  .. code-block:: yaml
+
+      dnsaas_hosts:
+        infra1:
+          ip: 172.20.236.111
+        infra2:
+          ip: 172.20.236.112
+        infra3:
+          ip: 172.20.236.113
+
+* Create respective LXC containers (skip this step for metal deployments):
+
+  .. code-block:: console
+
+     openstack-ansible openstack.osa.containers_lxc_create --limit designate_all,dnsaas_hosts
+
+* Run service deployment playbook:
+
+  .. code-block:: console
+
+     openstack-ansible openstack.osa.designate
+
+For more information, please refer to the `OpenStack-Ansible project documentation <https://docs.openstack.org/project-deploy-guide/openstack-ansible/latest/>`_.
+
+Always verify that the integration is successful and that the service behaves
+correctly before using it in a production environment.
+
 Dependencies
 ~~~~~~~~~~~~
 
-This role needs pip >= 7.1 installed on the target host.
-
 This role needs the following variables defined:
 
 .. code-block:: yaml