【正文】 ............................................. 17 管理界面與命令 .................................................................................................... 19 hdfs 運行狀態(tài)界面 ........................................................................................... 19 Mapreduce 的運行狀態(tài)界面 ........................................................................... 20 直接的命令行查看 .......................................................................................... 20 運行的進程查看 .............................................................................................. 21 5 架構分析 ..................................................................................................................... 23 HDFS .................................................................................................................... 23 HDFS 的三個重要角色 .................................................................................... 24 HDFS 設計特點 ............................................................................................... 25 MapReduce .......................................................................................................... 26 北京寬連十方數字技術有限公司 公開 絕密 算法介紹 ......................................................................................................... 26 Hadoop 框架下的 mapreduce .......................................................................... 28 綜合架構分析 ........................................................................................................ 29 6 Hadoop 的應用 ............................................................................................................ 38 7 系統(tǒng)維護 ..................................................................................................................... 39 Hadoop 的系統(tǒng)監(jiān)控 ............................................................................................... 39 Hadoop 中的命令（ Command）總結 ...................................... 錯誤！未定義書簽。 NameNode 與 JobTracker 單點故障說明 ............................................................... 40 經驗總結 ............................................................................................................... 40 如何在一個 hadoop 集群新增或刪除一些機器而不重啟 ........................................ 41 新增節(jié)點 ......................................................................................................... 41 刪除節(jié)點 ......................................................................................................... 41 其它日常問題說明 ................................................................................................ 43 datanode 啟動失敗，各 slave 節(jié)點的 namespaceIDs 與 masters不同 ............... 43 taskTracker 和 jobTracker 啟動失敗 ............................................................... 44 Shuffle Error: Exceeded MAX_FAILED_UNIQUE_FETCHES。 bailingout ... 45 Too many fetchfailures .................................................................................. 45 能夠啟動 datanode，但 無法訪問，也無法結束的錯誤 ................................... 45 : Could not obtain block: ................................................. 46 : Java heap space ........................................... 46 解決 hadoop OutOfMemoryError 問題： ......................................................... 46 Hadoop : ......................................................................... 46 防火墻的端口開放要求 ......................................................................................... 47 與 HDFS 有關的地址及端口屬性 .............................................................