private HostName getLoadBalancerName(HostName loadbalancerName, List<ConfigServerSpec> configServerSpecs) {
        // Set lbaddress, or use first hostname if not specified.
        // TODO: Remove this method and use the loadbalancerName directly
        return Optional.ofNullable(loadbalancerName)
                .orElseGet(
                        () -> HostName.of(configServerSpecs.stream()
                                                           .findFirst()
                                                           .map(ConfigServerSpec::getHostName)
                                                           .orElse("unknown") // Currently unable to test this, hence the unknown
                        ));
    }
Allocate a container cluster without a nodes tag
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java