private List<Configserver> createSingleConfigServer(DeployState deployState, TreeConfigProducer<?> parent) {
        SimpleConfigProducer<AnyConfigProducer> configServers = new SimpleConfigProducer<>(parent, "configservers");
        Configserver configServer = new Configserver(configServers, "configserver", Configserver.defaultRpcPort);
        configServer.setHostResource(parent.hostSystem().getHost(Container.SINGLENODE_CONTAINER_SERVICESPEC));
        configServer.initService(deployState);
        return List.of(configServer);
    }
Fallback when no config server is specified
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/DomAdminV2Builder.java