Add document about how configure and use profiler in vitrage

Change-Id: I9e14d3846ac97412a2811f363b343d920d944b93
Implements: blueprint osprofiler-support

doc/source/installation-and-configuration.rst

@@ -47,3 +47,4 @@ Configuration
    alarm-severity-config
    zabbix_vitrage
    notifier-snmp-plugin
+   profiler-config

doc/source/profiler-config.rst

@@ -0,0 +1,61 @@
+==================
+Configure profiler
+==================
+
+Overview
+========
+
+`osprofiler`_, the Cross-project profiling library for OpenStack, is integrated in Vitrage to generate 1 trace per
+request, that goes through all involved services.
+
+.. _osprofiler: https://docs.openstack.org/osprofiler/latest/
+
+Configuration
+=============
+
+Profiling must be enabled **explicitly** in Vitrage configuration file::
+
+
+    [profiler]
+
+    enabled = true
+    hmac_keys = SECRET_KEY
+    #connection_string = messaging://
+
+- ``hmac_key`` will be used in client to sign a request with profiling enabled
+- ``connection_string`` specify the storage driver to collect tracing data, default to ceilometer via messaging
+
+Please refer to `osprofiler user manual`_ for details
+
+.. _osprofiler user manual: https://docs.openstack.org/osprofiler/latest/user/index.html
+
+Usage
+=====
+
+Use ``--profile`` option in Vitrage CLI to send a request with profiling enabled, e.g.::
+
+    vitrage --profile SECRET_KEY topology show
+
+The key must match the `hmac_keys` configured in the server.
+
+The uuid of trace will be prepended to the result::
+
+    To display trace use the command:
+
+      osprofiler trace show --html 8c2a594b-bb26-4a00-a408-fd378ae3566b
+
+    {
+      "directed": true,
+      "graph": {},
+      "nodes": [],
+      "links": [],
+      "multigraph": true
+    }%
+
+Follow the help message above to show the trace file with ``osprofiler`` client::
+
+    osprofiler trace show --html 8c2a594b-bb26-4a00-a408-fd378ae3566b
+
+.. image:: ./images/osprofiler-html-output.png
+   :width: 100%
+   :align: center