private static void addConfiguredComponents(DeployState deployState, ContainerCluster<? extends Container> cluster,
                                                Element parent, String componentName) {
        for (Element component : XML.getChildren(parent, componentName)) {
            ModelIdResolver.resolveModelIds(component, deployState.isHosted());
            cluster.addComponent(new DomComponentBuilder().build(deployState, cluster, component));
        }
    }
Allocate a container cluster without a nodes tag
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java