private List<ApplicationContainer> createNodesFromHosts(Map<HostResource, ClusterMembership> hosts,
                                                            ApplicationContainerCluster cluster,
                                                            DeployState deployState) {
        List<ApplicationContainer> nodes = new ArrayList<>();
        for (Map.Entry<HostResource, ClusterMembership> entry : hosts.entrySet()) {
            String id = "container." + entry.getValue().index();
            ApplicationContainer container = new ApplicationContainer(cluster, id, entry.getValue().retired(), entry.getValue().index(), deployState);
            container.setHostResource(entry.getKey());
            container.initService(deployState);
            nodes.add(container);
        }
        return nodes;
    }
Allocate a container cluster without a nodes tag
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java