private String findDominantVtag(
                final Map<Integer, NodeInfo> storageNodeInfos,
                final Map<Integer, NodeInfo> distributorNodeInfos) {
            final List<NodeInfo> nodeInfos = new ArrayList<>();
            nodeInfos.addAll(storageNodeInfos.values());
            nodeInfos.addAll(distributorNodeInfos.values());

            final Map<String, Integer> versionTagToCount = new HashMap<>();
            int maxCount = -1;
            String dominantVtag = null;
            for (NodeInfo nodeInfo : nodeInfos) {
                final String buildTag = nodeInfo.getVtag();
                Integer count = versionTagToCount.get(buildTag);
                count = count == null ? 1 : count + 1;
                versionTagToCount.put(buildTag, count);
                if (count > maxCount) {
                    maxCount = count;
                    dominantVtag = buildTag;
                }
            }
            return dominantVtag == null ? TAG_NOT_SET : dominantVtag;
        }
Renders web page with cluster status.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/status/statuspage/VdsClusterHtmlRenderer.java