public static Set<HostName> getHostsUsedByServiceCluster(ServiceCluster serviceCluster) {
        return serviceCluster.serviceInstances().stream()
                .map(ServiceInstance::hostName)
                .collect(toSet());
    }
Utility methods for working with service monitor model entity objects.

@author bakksjo
orchestrator/src/main/java/com/yahoo/vespa/orchestrator/OrchestratorUtil.java