Expose image locations by default when in use with a Ceph backend to support copy-on-write cloning in cinder and nova

config.yaml

@@ -255,3 +255,10 @@ options:
       wait for you to execute the openstack-upgrade action for this charm on
       each unit. If False it will revert to existing behavior of upgrading
       all units on config change.
+  expose-image-locations:
+    type: boolean
+    default: True
+    description: |
+      Expose underlying image locations via the API when using Ceph for image
+      storage.  Only disable this option if you do not wish to use copy-on-write
+      clones of RAW format images with Ceph in Cinder and Nova.

hooks/glance_contexts.py

@@ -32,6 +32,7 @@ class CephGlanceContext(OSContextGenerator):
             # pool created based on service name.
             'rbd_pool': service,
             'rbd_user': service,
+            'expose_image_locations': config('expose-image-locations')
         }
 
 

templates/kilo/glance-api.conf

@@ -20,6 +20,8 @@ registry_host = {{ registry_host }}
 registry_port = 9191
 registry_client_protocol = http
 
+show_multiple_locations = {{ expose_image_locations }}
+
 {% if api_config_flags -%}
 {% for key, value in api_config_flags.iteritems() -%}
 {{ key }} = {{ value }}

unit_tests/test_glance_contexts.py

@@ -42,10 +42,13 @@ class TestGlanceContexts(CharmTestCase):
         self.is_relation_made.return_value = True
         service = 'glance'
         self.service_name.return_value = service
+        self.config.return_value = True
         self.assertEquals(
             contexts.CephGlanceContext()(),
             {'rbd_pool': service,
-             'rbd_user': service})
+             'rbd_user': service,
+             'expose_image_locations': True})
+        self.config.assert_called_with('expose-image-locations')
 
     def test_multistore(self):
         self.relation_ids.return_value = ['random_rid']