diff --git a/HACKING.rst b/HACKING.rst
index 307d7477..b29361a8 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -211,6 +211,25 @@ Example::
     LOG.error(msg % {"s_id": "1234", "m_key": "imageId"})
 
 
+Python 3.x compatibility
+------------------------
+Nova code should stay Python 3.x compatible. That means all Python 2.x-only
+constructs should be avoided. An example is
+
+    except x,y:
+
+Use
+
+    except x as y:
+
+instead. Other Python 3.x compatility issues, like e.g. print operator
+can be avoided in new code by using
+
+    from __future__ import print_function
+
+at the top of your module.
+
+
 Creating Unit Tests
 -------------------
 For every new feature, unit tests should be created that both test and
diff --git a/nova/tests/test_api.py b/nova/tests/test_api.py
index 949f5451..3c3ac6c6 100644
--- a/nova/tests/test_api.py
+++ b/nova/tests/test_api.py
@@ -309,7 +309,7 @@ class ApiEc2TestCase(test.TestCase):
 
         try:
             self.ec2.create_key_pair('test')
-        except boto_exc.EC2ResponseError, e:
+        except boto_exc.EC2ResponseError as e:
             if e.code == 'InvalidKeyPair.Duplicate':
                 pass
             else:
diff --git a/nova/tests/test_migrations.py b/nova/tests/test_migrations.py
index 00cfdbf6..9baf9eb6 100644
--- a/nova/tests/test_migrations.py
+++ b/nova/tests/test_migrations.py
@@ -219,7 +219,7 @@ class BaseMigrationTestCase(test.TestCase):
                 for key, value in defaults.items():
                     self.test_databases[key] = value
                 self.snake_walk = cp.getboolean('walk_style', 'snake_walk')
-            except ConfigParser.ParsingError, e:
+            except ConfigParser.ParsingError as e:
                 self.fail("Failed to read test_migrations.conf config "
                           "file. Got error: %s" % e)
         else: