diff --git a/config_tempest/api_discovery.py b/config_tempest/api_discovery.py
index efe632df..3edb0e24 100644
--- a/config_tempest/api_discovery.py
+++ b/config_tempest/api_discovery.py
@@ -53,7 +53,7 @@ class Service(object):
                 http = urllib3.PoolManager()
             r = http.request('GET', url, headers=self.headers)
         except Exception as e:
-            LOG.error("Request on service '%s' with url '%s' failed" %
+            LOG.error("Request on service '%s' with url '%s' failed",
                       (self.name, url))
             raise e
         if r.status >= 400:
@@ -153,8 +153,8 @@ def get_identity_v3_extensions(keystone_v3_url):
                          verify=False,
                          headers={'Accept': 'application/json-home'})
     except requests.exceptions.RequestException as re:
-        LOG.error("Request on service '%s' with url '%s' failed" %
-                  ('identity', keystone_v3_url))
+        LOG.error("Request on service '%s' with url '%s' failed",
+                  'identity', keystone_v3_url)
         raise re
     ext_h = 'http://docs.openstack.org/api/openstack-identity/3/ext/'
     res = [x for x in json.loads(r.content)['resources'].keys()]
diff --git a/config_tempest/config_tempest.py b/config_tempest/config_tempest.py
index 87086114..853c065c 100755
--- a/config_tempest/config_tempest.py
+++ b/config_tempest/config_tempest.py
@@ -176,7 +176,7 @@ def main():
     configure_discovered_services(conf, services)
     configure_boto(conf, services)
     configure_horizon(conf)
-    LOG.info("Creating configuration file %s" % os.path.abspath(args.out))
+    LOG.info("Creating configuration file %s", os.path.abspath(args.out))
     with open(args.out, 'w') as f:
         conf.write(f)
 
@@ -505,7 +505,7 @@ def give_role_to_user(tenants_client, roles_client, users_client, username,
     if not role_ids:
         if role_required:
             raise Exception("required role %s not found" % role_name)
-        LOG.debug("%s role not required" % role_name)
+        LOG.debug("%s role not required", role_name)
         return
     role_id = role_ids[0]
     try:
@@ -809,7 +809,7 @@ def _download_file(url, destination):
 
 def _download_image(client, id, path):
     """Download file from glance."""
-    LOG.info("Downloading image %s to %s" % (id, path))
+    LOG.info("Downloading image %s to %s", (id, path))
     body = client.show_image_file(id)
     LOG.debug(type(body.data))
     with open(path, 'wb') as out:
diff --git a/tox.ini b/tox.ini
index 52cb3bbe..0b029dff 100644
--- a/tox.ini
+++ b/tox.ini
@@ -36,5 +36,6 @@ commands = oslo_debug_helper {posargs}
 
 show-source = True
 ignore = E123,E125
+enable-extensions = H106,H230,H904
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build