感覺程序員的世界真是一個變幻無常且精彩絕倫的世界，每次跑程序都會發現不一樣的問題。今天跑MapReduce程序來統計郵箱次數時遇到了一個問題，明明一樣的代碼，別人能跑，我卻跑不了。我相信，基本做這行的都遇到過這種問題。好了，話不多說，來聊聊今天的錯誤吧。

　　根據日誌查看到報的錯誤為：No lease on /目錄: File does not exist. [Lease. Holder: DFSClient_NONMAPREDUCE_-2059237550_1, pendingcreates: 8]，詳細信息如下面日誌所示。

2018-04-02 15:05:04,669 DEBUG [org.apache.hadoop.ipc.Client] - IPC Client (2124974876) connection to ******* from Zimo sending #55
2018-04-02 15:05:04,670 DEBUG
 
 [org.apache.hadoop.ipc.Client] - IPC Client (2124974876) connection to ******* from Zimo got value #55
2018-04-02 15:05:04,671 WARN [org.apache.hadoop.hdfs.DFSClient] - DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.LeaseExpiredException): No lease on /email/out/_temporary/0/_temporary/attempt_local1331388695_0001_r_000000_0/163-r-00000: File does not exist. [Lease.  Holder: DFSClient_NONMAPREDUCE_-979457887_1, pendingcreates: 8
 
]
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkLease(FSNamesystem.java:2737)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.analyzeFileState(FSNamesystem.java:2543)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2454)
    at org
 
.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:555)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:387)
    at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java:59582)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2048)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2044)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2042)

    at org.apache.hadoop.ipc.Client.call(Client.java:1347)
    at org.apache.hadoop.ipc.Client.call(Client.java:1300)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
    at com.sun.proxy.$Proxy9.addBlock(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:186)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
    at com.sun.proxy.$Proxy9.addBlock(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:330)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1226)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1078)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:514)
2018-04-02 15:05:04,671 ERROR [org.apache.hadoop.hdfs.DFSClient] - Failed to close file /email/out/_temporary/0/_temporary/attempt_local1331388695_0001_r_000000_0/163-r-00000
org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.LeaseExpiredException): No lease on /email/out/_temporary/0/_temporary/attempt_local1331388695_0001_r_000000_0/163-r-00000: File does not exist. [Lease.  Holder: DFSClient_NONMAPREDUCE_-979457887_1, pendingcreates: 8]
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkLease(FSNamesystem.java:2737)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.analyzeFileState(FSNamesystem.java:2543)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2454)
    at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:555)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:387)
    at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java:59582)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2048)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2044)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2042)

    at org.apache.hadoop.ipc.Client.call(Client.java:1347)
    at org.apache.hadoop.ipc.Client.call(Client.java:1300)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
    at com.sun.proxy.$Proxy9.addBlock(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:186)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
    at com.sun.proxy.$Proxy9.addBlock(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:330)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1226)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1078)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:514)
2018-04-02 15:05:04,672 DEBUG [org.apache.hadoop.ipc.Client] - Stopping client

　　在前面跑MapReduce程序的時候沒有出現過這個錯誤，就今天遇到了。遇到這個錯誤時需要在Reducer代碼中加上cleanup方法以重新執行。

　　protected void cleanup(Context context) throws IOException,InterruptedException {
            multipleOutputs.close();
   }

　　cleanup()方法會被MapReduce框架僅且執行一次，在執行完畢Map任務後，進行相關變量或資源的釋放工作。若是將釋放資源工作放入方法map()中，也會導致Mapper任務在解析、處理每一行文本後釋放資源，而且在下一行文本解析前還要重復初始化，導致反復重復，程序運行效率不高！

　　現在我們再重新運行一次程序就會發現問題已經解決了！

以上就是博主為大家介紹的這一板塊的主要內容，這都是博主自己的學習過程，希望能給大家帶來一定的指導作用，有用的還望大家點個支持，如果對你沒用也望包涵，有錯誤煩請指出。如有期待可關註博主以第一時間獲取更新哦，謝謝！

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No lease on /目錄: File does not exist. [Lease. Holder: DFSClient_NONMAPREDUCE_-2059237550_1, pendingcreates: 8]錯誤及解決方法