code: private static AlluxioConfiguration loadClusterConfiguration(GetConfigurationPResponse response,
        AlluxioConfiguration conf) {
      String clientVersion = conf.get(PropertyKey.VERSION);
      LOG.info("Alluxio client (version {}) is trying to load cluster level configurations",
          clientVersion);
      List<alluxio.grpc.ConfigProperty> clusterConfig = response.getConfigsList();
      Properties clusterProps = loadClientProperties(clusterConfig, (key, value) ->
          String.format("Loading property: %s (%s) -> %s", key, key.getScope(), value));
      // Check version.
      String clusterVersion = clusterProps.get(PropertyKey.VERSION).toString();
      if (!clientVersion.equals(clusterVersion)) {
        LOG.warn("Alluxio client version ({}) does not match Alluxio cluster version ({})",
            clientVersion, clusterVersion);
        clusterProps.remove(PropertyKey.VERSION);
      }
      // Merge conf returned by master as the cluster default into conf object
      AlluxioProperties props = conf.copyProperties();
      props.merge(clusterProps, Source.CLUSTER_DEFAULT);
      // Use the constructor to set cluster defaults as being loaded.
      InstancedConfiguration updatedConf = new InstancedConfiguration(props, true);
      updatedConf.validate();
      LOG.info("Alluxio client has loaded cluster level configurations");
      return updatedConf;
    }
docs: Loads the cluster level configuration from the get configuration response, and merges it with
  the existing configuration.
  
  @param response the get configuration RPC response
  @param conf the existing configuration
  @return the merged configuration