private List<ApplicationContainer> createNodesFromNodeList(DeployState deployState, ApplicationContainerCluster cluster, Element nodesElement) {
        List<ApplicationContainer> nodes = new ArrayList<>();
        int nodeIndex = 0;
        for (Element nodeElem: XML.getChildren(nodesElement, "node")) {
            nodes.add(new ContainerServiceBuilder("container." + nodeIndex, nodeIndex).build(deployState, cluster, nodeElem));
            nodeIndex++;
        }
        return nodes;
    }
Allocate a container cluster without a nodes tag
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java