上次雖然把環境搭好了，但是實際執行起來一堆錯誤，下面簡述一下踩的坑。

1、hadoop fs -put上傳檔案失敗

報錯資訊：（test資料夾是已經成功建好的）

[[email protected] ~]# hadoop fs -put test1.txt /test
18/12/27 03:50:53 WARN hdfs.DFSClient: DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /test/test1.txt._COPYING_ could only be replicated to 0
 
 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1620)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getNewBlockTargets(FSNamesystem.java:
 
3135)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:3059)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:725)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:
 
493)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:982)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2217)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2213)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1762)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2211)

        at org.apache.hadoop.ipc.Client.call(Client.java:1476)
        at org.apache.hadoop.ipc.Client.call(Client.java:1413)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:229)
        at com.sun.proxy.$Proxy10.addBlock(Unknown Source)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:418)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:191)
        at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
        at com.sun.proxy.$Proxy11.addBlock(Unknown Source)
        at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1603)
        at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1388)
        at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:554)
put: File /test/test1.txt._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.

Linux報的錯誤是datanode節點不存在，但是去slave機器上jps發現datanode執行的好好的。然後去網上查詢資料，有部落格說是因為沒關閉防火牆，沒有訪問許可權， 好嘛，又去關防火牆，結果命令又不存在，因為實驗室分配的機器太老了（好像是Red Hat4.x Linux3.x版本的），又吭哧吭哧裝了半天命令，再檢視防火牆，是關閉的啊，我真的是頭疼。

然後接著找其他解決方案吧，參考資料3說可能是format次數太多，導致每次的spaceId不一致，現在想來，我確實是format了很多次，那就先來試試。

首先停止所有服務 stop-all.sh。

然後刪除 core-site.xml 中hadoop.tmp.dir對應的資料夾下所有資料，注意：不是把這個資料夾也刪掉！ sudo rm -rf /root/software/hadooptmp 

在之後重新格式化namenode，在bin目錄下 hdfs namenode -format 

重新啟動hadoop叢集，start-all.sh

再來試試，還是不行。。

2、

參考資料：

1、Ubuntu16.04 上執行 Hadoop2.7.3 自帶example wordCount摸索記錄

2、Failed to execute operation: No such file or directory(systemctl enable iptables.service)

3、File /input/data.txt._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1)