private static Map<ClusterId, List<ServiceInfo>> clusterControllerClusters(ModelResult application) {
        return application.getModel().getHosts().stream()
                .flatMap(host -> host.getServices().stream())
                .filter(service -> service.getServiceType().equals(CLUSTERCONTROLLER_CONTAINER.serviceName))
                .collect(Collectors.groupingBy(service -> new ClusterId(service.getProperty("clustername").get())));

    }
Retrieves reindexing status from cluster controllers over HTTP

@author bjorncs
configserver/src/main/java/com/yahoo/vespa/config/server/application/DefaultClusterReindexingStatusClient.java