+If the host part of @ListenURL@ is ambiguous, in the sense that more than one system host is able to listen on that address (e.g., @localhost@), configure each host's startup scripts to set the environment variable @ARVADOS_SERVICE_INTERNAL_URL@ to the @InternalURLs@ key that will reach that host. In the example above, this would be @ARVADOS_SERVICE_INTERNAL_URL=https://ctrl-0.internal@.
+
+If the cluster has just a single node running all of the Arvados server processes, configuration can be simplified: