private List<ApplicationContainer> allocateWithoutNodesTag(ApplicationContainerCluster cluster, ConfigModelContext context) {
        DeployState deployState = context.getDeployState();
        HostSystem hostSystem = cluster.hostSystem();
        if (deployState.isHosted()) {
            // request just enough nodes to satisfy environment capacity requirement
            int nodeCount = deployState.zone().environment().isProduction() ? 2 : 1;
            deployState.getDeployLogger().logApplicationPackage(Level.INFO, "Using " + nodeCount + " nodes in " + cluster);
            var nodesSpec = NodesSpecification.dedicated(nodeCount, context);
            ClusterSpec.Id clusterId = ClusterSpec.Id.from(cluster.getName());
            var hosts = nodesSpec.provision(hostSystem,
                                            ClusterSpec.Type.container,
                                            clusterId,
                                            zoneEndpoint(context, clusterId),
                                            deployState.getDeployLogger(),
                                            false,
                                            context.clusterInfo().build());
            return createNodesFromHosts(hosts, cluster, context.getDeployState());
        }
        else {
            return singleHostContainerCluster(cluster, hostSystem.getHost(Container.SINGLENODE_CONTAINER_SERVICESPEC), context);
        }
    }
Allocate a container cluster without a nodes tag
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java