diff --git a/setup.cfg b/setup.cfg
index 7c23aa920e..812d3565ed 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -39,6 +39,12 @@ oslo.config.opts =
 setup-hooks =
     pbr.hooks.setup_hook
 
+[extras]
+mysql =
+  PyMySQL>=0.7.6  # MIT
+postgres =
+  psycopg2>=2.5  # LGPL/ZPL
+
 [build_sphinx]
 all_files = 1
 build-dir = doc/build
diff --git a/tox.ini b/tox.ini
index d01a707b62..f132cde34d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,6 +4,7 @@ skipsdist = True
 envlist = py35,py34,py27,pep8
 
 [testenv]
+extras = {env:RALLY_EXTRAS:}
 setenv = VIRTUAL_ENV={envdir}
          HOME={homedir}
          LANG=en_US.UTF-8