调用从kv.local/172.20.12.168到localhost：8020连接异常失败，使用tera时

Question

我正在与hadoop teragen一起检查hadoop mapreduce与terasort的基准测试。 但是当我运行下面的命令，

Hadoop的罐子/Users/**/Documents/hadoop-2.6.4/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.4.jar teragen - Dmapreduce.job.maps = 1001吨随机数据

我得到了以下异常，

17/06/01 15:09:21 WARN util.NativeCodeLoader: Unable to load native-hadoop 
library for your platform... using builtin-java classes where applicable 
17/06/01 15:09:22 INFO client.RMProxy: Connecting to ResourceManager at /127.0.0.1:8032 
17/06/01 15:09:23 INFO terasort.TeraSort: Generating -727379968 using 100 
17/06/01 15:09:23 INFO mapreduce.JobSubmitter: number of splits:100 
17/06/01 15:09:23 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1496303775726_0003 
17/06/01 15:09:23 INFO impl.YarnClientImpl: Submitted application application_1496303775726_0003 
17/06/01 15:09:23 INFO mapreduce.Job: The url to track the job: http://localhost:8088/proxy/application_1496303775726_0003/ 
17/06/01 15:09:23 INFO mapreduce.Job: Running job: job_1496303775726_0003 
17/06/01 15:09:27 INFO mapreduce.Job: Job job_1496303775726_0003 running in uber mode : false 
17/06/01 15:09:27 INFO mapreduce.Job: map 0% reduce 0% 
17/06/01 15:09:27 INFO mapreduce.Job: Job job_1496303775726_0003 failed with state FAILED due to: Application application_1496303775726_0003 failed 2 times due to AM Container for appattempt_1496303775726_0003_000002 exited with exitCode: -1000 
For more detailed output, check application tracking page:http://localhost:8088/proxy/application_1496303775726_0003/Then, click on links to logs of each attempt. 
Diagnostics: Call From KV.local/172.20.12.168 to localhost:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused 
java.net.ConnectException: Call From KV.local/172.20.12.168 to localhost:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) 
    at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:791) 
    at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:731) 
    at org.apache.hadoop.ipc.Client.call(Client.java:1473) 
    at org.apache.hadoop.ipc.Client.call(Client.java:1400) 
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:232) 
    at com.sun.proxy.$Proxy34.getFileInfo(Unknown Source) 
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:752) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:498) 
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:187) 
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102) 
    at com.sun.proxy.$Proxy35.getFileInfo(Unknown Source) 
    at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1977) 
    at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1118) 
    at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1114) 
    at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81) 
    at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1114) 
    at org.apache.hadoop.yarn.util.FSDownload.copy(FSDownload.java:251) 
    at org.apache.hadoop.yarn.util.FSDownload.access$000(FSDownload.java:61) 
    at org.apache.hadoop.yarn.util.FSDownload$2.run(FSDownload.java:359) 
    at org.apache.hadoop.yarn.util.FSDownload$2.run(FSDownload.java:357) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at javax.security.auth.Subject.doAs(Subject.java:422) 
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1656) 
    at org.apache.hadoop.yarn.util.FSDownload.call(FSDownload.java:356) 
    at org.apache.hadoop.yarn.util.FSDownload.call(FSDownload.java:60) 
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) 
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) 
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
    at java.lang.Thread.run(Thread.java:745) 
Caused by: java.net.ConnectException: Connection refused 
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) 
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717) 
    at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206) 
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:530) 
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:494) 
    at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:608) 
    at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:706) 
    at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:369) 
    at org.apache.hadoop.ipc.Client.getConnection(Client.java:1522) 
    at org.apache.hadoop.ipc.Client.call(Client.java:1439) 
    ... 31 more 

由于错误显示，它不能够连接到本地主机：8020，但是当我再检查一下namenode Web UI，它显示namenode是活动的。请看下面的截图：

我发现与此相关的很多帖子，但没有帮助我。我还检查了主机文件，其中包含以下行：

127.0.0.1本地主机

172.20.12.168本地主机

任何人都可以帮我整理出这个问题？

Answer 1

以下步骤帮助我解决这个问题：

1. 停止所有的服务。

2. 删除hdfs-site.xml中指定的namenode和datanode目录。

3. 创建新的namenode和datanode目录并相应地修改hdfs-site.xml。

4. 核心-site.xml中

   ，做如下修改或添加以下属性：

   <property> 
       <name>fs.defaultFS</name> 
       <value>hdfs://172.20.12.168/</value> 
   </property> 
   <property> 
       <name>fs.default.name</name> 
       <value>hdfs://172.20.12.168:8020</value> 
   </property> 
   

5. 让Hadoop中-2.6.4以下修改/ etc/Hadoop的/ hadoop-env.sh文件：

   export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home 
   

6. 重新启动DFS，纱和先生如下：

   start-dfs.sh 
   start-yarn.sh 
   mr-jobhistory-daemon.sh start historyserver