hadoop eclipse 运行报错

最近安装了hadoop的0.20.2 版本，然后再eclipse中安装了 对应的插件，

在运行 示例中的 程序  WordCount.java 的时候，出现了很多错误：

1.   配置连接的 hadoop    

      Location name（取个名字）
      Map/Reduce Master（Job Tracker的IP和端口，根据mapred-site.xml中配置的mapred.job.tracker来填写）
      DFS Master（Name Node的IP和端口，根据core-site.xml中配置的fs.default.name来填写）

2.  首次运行报错：

      2010-07-17 16:56:14,968 WARN org.apache.hadoop.mapred.TaskTracker: Error running child

org.apache.hadoop.security.AccessControlException: org.apache.hadoop.security.AccessControlException: Permission denied: user=DrWho, access=WRITE, inode="Administrator":Administrator:supergroup:rwxr-xr-x

      当前的用户是DrWho，无权限，同样检查C:\cygwin\home\Administrator\hadoop-0.20.2\logs中生成的job配置信息（如：job_201007171612_0006_conf.xml
），可看到以下设置：
<property>
 <name>user.name</name>
 <value>DrWho</value>
</property>
<property>
 <name>hadoop.job.ugi</name>
 <value>DrWho,Tardis</value>
</property>
    解决办法：http://forum.hadoop.tw/viewtopic.php?f=4&t=13&view=previous
    $ bin/hadoop dfs -chmod 777 /user/Administrator

3.   修改后，又出现新的错误：

       忘记错误时什么了，网上查是没有安装 Cygwin ，于是开始安装

4.   修改后运行报错

      eclipse报错：

     13/04/18 13:51:53 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
Exception in thread "main" java.net.UnknownHostException: unknown host: hadoopserver
at org.apache.hadoop.ipc.Client$Connection.<init>(Client.java:195)
at org.apache.hadoop.ipc.Client.getConnection(Client.java:850)
at org.apache.hadoop.ipc.Client.call(Client.java:720)
at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:220)
at $Proxy1.getProtocolVersion(Unknown Source)
at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:359)
at org.apache.hadoop.hdfs.DFSClient.createRPCNamenode(DFSClient.java:106)
at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:207)
at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:170)
at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:82)
at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:1378)
at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:66)
at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:1390)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:196)
at org.apache.hadoop.fs.Path.getFileSystem(Path.java:175)
at org.apache.hadoop.mapred.JobClient.getFs(JobClient.java:463)
at org.apache.hadoop.mapred.JobClient.configureCommandLineOptions(JobClient.java:567)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:761)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:432)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:447)
at WordCount.main(WordCount.java:75)

      namenode 报错：

      2013-04-17 20:18:27,592 INFO org.apache.hadoop.ipc.Server: IPC Server listener on 9002: readAndProcess threw exception java.io.IOException: Connection reset by peer. Count of bytes read: 0
      java.io.IOException: Connection reset by peer

   

     报错为  server.isUnresolved()     hadoop 无法将主机名解析为地址

      修改/etc/sysconfig/network     修改文件内的主机名   hostname 改为hadoopserver