从eclipse提交hadoop作业时出现ConnectException

Question

我正在尝试从 windows 上的 eclipse 向 hadoop-2.5.0（安装在虚拟机上运行的 ubuntu 14.04.1 服务器上）提交一份工作（一个简单的字数统计）。在作业配置中，我将“fs.defaultFS”设置为“hdfs://192.168.2.216:8020”（如thread 中所建议的那样）但是当我运行主程序时出现以下异常：

WARN  - NativeCodeLoader           - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
ERROR - Shell                      - Failed to locate the winutils binary in the hadoop binary path
Exception in thread "main" java.net.ConnectException: Call From EL-OUED/192.168.2.8 to 192.168.2.216:8020 failed on connection exception: java.net.ConnectException: Connection refused: no further information; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:783)
    at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:730)
    at org.apache.hadoop.ipc.Client.call(Client.java:1414)
    at org.apache.hadoop.ipc.Client.call(Client.java:1363)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
    at com.sun.proxy.$Proxy14.getFileInfo(Unknown Source)
    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:190)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:103)
    at com.sun.proxy.$Proxy14.getFileInfo(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:699)
    at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1762)
    at org.apache.hadoop.hdfs.DistributedFileSystem$17.doCall(DistributedFileSystem.java:1124)
    at org.apache.hadoop.hdfs.DistributedFileSystem$17.doCall(DistributedFileSystem.java:1120)
    at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
    at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1120)
    at org.apache.hadoop.fs.FileSystem.exists(FileSystem.java:1398)
    at org.apache.hadoop.mapreduce.lib.output.FileOutputFormat.checkOutputSpecs(FileOutputFormat.java:145)
    at org.apache.hadoop.mapreduce.JobSubmitter.checkSpecs(JobSubmitter.java:458)
    at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:343)
    at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1285)
    at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1282)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1556)
    at org.apache.hadoop.mapreduce.Job.submit(Job.java:1282)
    at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1303)
    at com.heavenize.hadoop.WordCountMR.main(WordCountMR.java:55)
Caused by: java.net.ConnectException: Connection refused: no further information
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:735)
    at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:529)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:493)
    at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:604)
    at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:699)
    at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:367)
    at org.apache.hadoop.ipc.Client.getConnection(Client.java:1462)
    at org.apache.hadoop.ipc.Client.call(Client.java:1381)
    ... 28 more

此外，在检查 hadoop 上的连接配置时，它似乎正在侦听/接受 127.0.0.1:8020 上的连接。

$netstat -lent | grep 8020
tcp        0      0 127.0.0.1:8020          0.0.0.0:*               LISTEN      1001       10380

这是core-site.xml的内容，不知道是不是这个问题的根源，如何解决？

<configuration>
  <property>
    <name>fs.default.name</name>
    <value>hdfs://localhost</value>
  </property>
</configuration>

Answer 1

基本上你的namenode正在监听localhost接口，因此它只允许来自127.0.0.1的连接。正如您所建议的，错误确实在 fs.default.name 参数中，应修改为使用主机名而不是 localhost。

注意 /etc/hosts 应该包含类似的行

192.168.2.216 hostname.fully.qualified.domain.com hostname

您可以运行命令“hostname”和“hostname -f”来验证主机名是否正确设置。 "hostname" 应该返回 gethostname 返回的系统名称，而 "hostname -f" 应该返回系统的 fqdn。