public static Set<ServiceCluster> getClusterControllerServiceClusters(ApplicationInstance application) {
        return application.serviceClusters().stream()
                    .filter(VespaModelUtil::isClusterController)
                    .collect(Collectors.toSet());
    }
@return The set of all Cluster Controller service instances for the application.
orchestrator/src/main/java/com/yahoo/vespa/orchestrator/model/VespaModelUtil.java