public Map<String, ContentCluster> getContentClusters() {
        Map<String, ContentCluster> clusters = new LinkedHashMap<>();
        for (Content model : configModelRepo.getModels(Content.class)) {
            clusters.put(model.getId(), model.getCluster());
        }
        return Collections.unmodifiableMap(clusters);
    }
Returns a map of content clusters by ID
config-model/src/main/java/com/yahoo/vespa/model/VespaModel.java