code: public static AlluxioConfiguration loadClusterDefaults(InetSocketAddress address,
        AlluxioConfiguration conf) throws AlluxioStatusException {
      if (shouldLoadClusterConfiguration(conf)) {
        GetConfigurationPResponse response = loadConfiguration(address, conf);
        conf = loadClusterConfiguration(response, conf);
      }
      return conf;
    }
docs: Loads cluster default values from the meta master.
  
  Only client scope properties will be loaded.
  If cluster level configuration has been loaded or the feature of loading configuration from
  meta master is disabled, no RPC will be issued.
  
  @param address the master address
  @param conf configuration to use
  @return a configuration object containing the original configuration merged with cluster
  defaults, or the original object if the cluster defaults have already been loaded