Clean up firewall rules on exit

Change-Id: I70f04366f60670776fa4863e3ede84ffcfdcb454
Closes-Bug: #1436880

ironic_discoverd/firewall.py

@@ -69,6 +69,15 @@ def _clean_up(chain):
     _iptables('-X', chain, ignore=True)
 
 
+def clean_up():
+    """Clean up everything before exiting."""
+    if not CONF.discoverd.manage_firewall:
+        return
+
+    _clean_up(CHAIN)
+    _clean_up(NEW_CHAIN)
+
+
 def update_filters(ironic=None):
     """Update firewall filter rules for introspection.
 

ironic_discoverd/main.py

@@ -188,6 +188,9 @@ def main(args=sys.argv[1:]):  # pragma: no cover
         logging.INFO if debug else logging.ERROR)
 
     init()
-    app.run(debug=debug,
-            host=CONF.discoverd.listen_address,
-            port=CONF.discoverd.listen_port)
+    try:
+        app.run(debug=debug,
+                host=CONF.discoverd.listen_address,
+                port=CONF.discoverd.listen_port)
+    finally:
+        firewall.clean_up()