diff --git a/Authors b/Authors
index 2653a631a99..c8b8269d9a7 100644
--- a/Authors
+++ b/Authors
@@ -22,6 +22,7 @@ Asbjørn Sannes <asbjorn.sannes@interhost.no>
 Ben McGraw <ben@pistoncloud.com>
 Ben Swartzlander <bswartz@netapp.com>
 Bilal Akhtar <bilalakhtar@ubuntu.com>
+Boris Filippov <bfilippov@griddynamics.com>
 Brad Hall <brad@nicira.com>
 Brad McConnell <bmcconne@rackspace.com>
 Brendan Maguire <B_Maguire@Dell.com>
diff --git a/nova/virt/libvirt/connection.py b/nova/virt/libvirt/connection.py
index da072be6453..00d7c1ed155 100644
--- a/nova/virt/libvirt/connection.py
+++ b/nova/virt/libvirt/connection.py
@@ -695,8 +695,7 @@ def snapshot(self, context, instance, image_href):
         else:
             metadata['disk_format'] = image_format
 
-        if 'container_format' in base:
-            metadata['container_format'] = base['container_format']
+        metadata['container_format'] = base.get('container_format', 'bare')
 
         # Find the disk
         xml_desc = virt_dom.XMLDesc(0)