Update README.md for running glance tests in tempest

1. Added how to run glance-tempest-plugin tests in local
   environment including rbac enablement
2. Added example of a working devstack local.conf

Change-Id: I915c2af98cadea08688550c1006be05c70718a8e

README.rst

@@ -7,8 +7,46 @@ This directory contains additional Ginder tempest tests.
 See the tempest plugin docs for information on using it:
 https://docs.openstack.org/tempest/latest/plugin.html#using-plugins
 
-To run all tests from this plugin, install glance into your environment. Then
-from the tempest directory run::
+To run all tests from this plugin,
+1. Clone  glance-tempest-plugin repo from github::
+
+    $ git clone https://opendev.org/openstack/glance-tempest-plugin
+
+2. Install the plugin::
+
+    $ pip3 install -e glance-tempest-plugin
+
+3. Confirm it's installed::
+
+    $ tempest list-plugins
+
+4. Create new file tempest.conf inside /etc/tempest directory and run with below
+   content, including rbac enablement
+
+::
+     [identity]
+     auth_version = v3
+     uri_v3 = <Full URI of the OpenStack Identity API>
+
+     [auth]
+     use_dynamic_credentials = True
+     admin_domain_name = Default
+     admin_project_name = admin
+     admin_password = admin
+     admin_username = admin
+     admin_system = True
+
+     [image_feature_enabled]
+     enforce_scope = True
+     os_glance_reserved = True
+     import_image = False
+
+     [enforce_scope]
+     glance = true
+
+
+
+5. Then from the tempest directory run::
 
     $ tox -e all -- glance_tempest_plugin
 
@@ -16,3 +54,23 @@ from the tempest directory run::
 It is expected that Glance third party CI's use the `all` tox environment
 above for all test runs. Developers can also use this locally to perform more
 extensive testing.
+
+Any typical devstack instance should be able to run all Glance plugin tests.
+For completeness, here is an example of a devstack local.conf that should
+work. Update backend information to fit your environment.
+
+::
+
+    [[local|localrc]]
+    ADMIN_PASSWORD=secret
+    SERVICE_TOKEN=$ADMIN_PASSWORD
+    MYSQL_PASSWORD=$ADMIN_PASSWORD
+    RABBIT_PASSWORD=$ADMIN_PASSWORD
+    SERVICE_PASSWORD=$ADMIN_PASSWORD
+    LOGFILE=$DEST/logs/stack.sh.log
+    LOGDAYS=2
+    SYSLOG=False
+    LOG_COLOR=False
+    RECLONE=yes
+    ENABLED_SERVICES=g-api,dstat,key
+    ENABLED_SERVICES+=,mysql,tempest