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: I3a9464eb3d6eeae06003816f6129908ac1d5d298

README.rst

@@ -14,6 +14,41 @@ This role will install the following:
 The role will configure Aodh to use MongoDB for data storage, but does
 not install or configure MongoDB.
 
+Adding The Service to Your OpenStack-Ansible Deployment
+-------------------------------------------------------
+
+To add a new service to your OpenStack-Ansible (OSA) deployment:
+
+* Define ``metering-alarm_hosts`` in your ``conf.d`` or ``openstack_user_config.yml``.
+  For example:
+
+  .. code-block:: yaml
+
+      metering-alarm_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 aodh_all,metering-alarm_hosts
+
+* Run service deployment playbook:
+
+  .. code-block:: console
+
+     openstack-ansible openstack.osa.aodh
+
+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.
+
 Default Variables
 =================