diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index 655558a1ef6..017c50c5d62 100644
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -661,6 +661,8 @@ def _rename_interfaces(renames, strict_present=True, strict_busy=True,
         cur['name'] = name
         cur_info[name] = cur
 
+    LOG.debug("Detected interfaces %s", cur_info)
+
     def update_byname(bymac):
         return dict((data['name'], data)
                     for data in cur_info.values())