Return non-zero exit code on failures

Launcher.wait() does not raise, it returns an integer code. Propagate it
to sys.exit() so that failures are correctly recognized.

Change-Id: I38bf39e4e4845415640b3468e9fb3029f70dcded

ironic/cmd/api.py

@@ -39,7 +39,7 @@ def main():
     launcher = ironic_service.process_launcher()
     server = wsgi_service.WSGIService('ironic_api', CONF.api.enable_ssl_api)
     launcher.launch_service(server, workers=server.workers)
-    launcher.wait()
+    sys.exit(launcher.wait())
 
 
 if __name__ == '__main__':

ironic/cmd/conductor.py

@@ -67,7 +67,7 @@ def main():
     issue_startup_warnings(CONF)
 
     launcher = service.launch(CONF, mgr, restart_method='mutate')
-    launcher.wait()
+    sys.exit(launcher.wait())
 
 
 if __name__ == '__main__':

ironic/cmd/singleprocess.py

@@ -49,4 +49,4 @@ def main():
     wsgi = wsgi_service.WSGIService('ironic_api', CONF.api.enable_ssl_api)
     launcher.launch_service(wsgi)
 
-    launcher.wait()
+    sys.exit(launcher.wait())

releasenotes/notes/service-exit-77bcf3a538fab4bc.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Services (``ironic``, ``ironic-api``, ``ironic-conductor``) now correctly
+    return a non-zero exit code on start-up failures.