private static NodeDataMetrics dataMetricsFromHostInfo(HostInfo hostInfo) {
        return new NodeDataMetrics(
                hostInfo.getMetrics().getValueAt(BUCKETS_METRIC_NAME, DEFAULT_SPACE_METRIC_DIMENSIONS),
                hostInfo.getMetrics().getValueAt(ENTRIES_METRIC_NAME, DEFAULT_SPACE_METRIC_DIMENSIONS),
                hostInfo.getMetrics().getValueAt(DOCS_METRIC_NAME,    DEFAULT_SPACE_METRIC_DIMENSIONS));
    }
Checks if a node can be upgraded.

@author Haakon Dybdahl
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/NodeStateChangeChecker.java