private static NodeResources freeCapacityOf(NodeList nodes, Node host) {
        return nodes.childrenOf(host).asList().stream()
                    .map(node -> node.flavor().resources().justNumbers())
                    .reduce(host.flavor().resources().justNumbers(), NodeResources::subtract);
    }
A version 6.163.20 will be returned as a number 163.020. The major
version can normally be inferred. As long as the micro version stays
below 1000 these numbers sort like Version.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/MetricsReporter.java