Add document for cetus datasource

Implements: blueprint add-cetus-datasource
Change-Id: I515292cc36532aee931a048247a05db6517a52f5

doc/source/contributor/cetus_datasource.rst

@@ -0,0 +1,32 @@
+================
+Cetus datasource
+================
+
+Cetus is a self-developed openstack solution of multi-k8s-clusters on openstack.
+The datasource allow user to intergrate cluster and pod resources and topology into Vitrage.
+The datasource provides how to get the Service-Endpoint-Url for self-developed internal projects based on openstack when
+there is no client library for this project.
+
+Note that currently we support only deploying multiple k8s clusters on nova.instance (nodes must be vm or bm instance).
+
+Datasource configuration
+------------------------
+
+1. Add cetus to list of datasources in ``/etc/vitrage/vitrage.conf``
+
+.. code::
+
+    [datasources]
+    types = ...,cetus.cluster,cetus.pod
+
+2. Modify and Get the Service-Endpoint-Url of the self-developed module based on openstack in ``cetus_driver_base.py``
+
+.. code::
+
+    def _get_cetus_url(service_name='cetusv1'):
+       pass
+
+**Note:** It is recommended to customize this method to get the Service-Url.
+
+3. Restart vitrage service in devstack/openstack
+

doc/source/contributor/configuration.rst

@@ -30,6 +30,8 @@ Datasources
    prometheus-datasource
    kapacitor-datasource
    tmfapi639-datasource
+   cetus_datasource
+
 
 Notifiers
 ---------