public String descriptiveName() {
        if (getServiceCluster().isController() || getServiceCluster().isConfigServer()) {
            return getHostnamePrefix();
        } else if (getServiceCluster().isControllerHost() || getServiceCluster().isConfigServerHost()) {
            return "host-admin on " + getHostnamePrefix();
        } else if (getServiceCluster().isTenantHost()) {
            return "host-admin on " + hostName.s();
        } else {
            return configId.s();
        }
    }
Get a name that can be used in e.g. config server logs that makes it easy to understand which
service instance this is.
application-model/src/main/java/com/yahoo/vespa/applicationmodel/ServiceInstance.java