code: public static void adjustMetaDirectoryNames(Configuration conf, String serviceKey) {
      adjustMetaDirectoryName(conf, DFS_SHARED_NAME_DIR0_KEY, serviceKey);
      adjustMetaDirectoryName(conf, DFS_SHARED_NAME_DIR1_KEY, serviceKey);
      adjustMetaDirectoryName(conf, DFS_SHARED_EDITS_DIR0_KEY, serviceKey);
      adjustMetaDirectoryName(conf, DFS_SHARED_EDITS_DIR1_KEY, serviceKey);
    }
docs: Append service name to each avatar meta directory name
  
  @param conf configuration of NameNode
  @param serviceKey the non-empty name of the name node service