在运行hadoop多节点集群时，我在主日志上看到下面的错误消息，可以建议怎么做吗。。？我需要创建一个新用户还是可以在这里提供我的现有计算机用户名
2013-07-25 19:41:11765 warn org.apache.hadoop.security.usergroupinformation:没有可用于用户webuser的组2013-07-25 19:41:11778 warn org.apache.hadoop.security.shellbasedunixgroupsmapping:尝试获取用户webuser org.apache.hadoop.util.shell$exitcodeexceptionwebuser:没有此类用户
hdfs-site.xml文件

<configuration>
<property>
  <name>dfs.replication</name>
  <value>2</value>
  <description>Default block replication.
  The actual number of replications can be specified when the file is created.
  The default is used if replication is not specified in create time.
  </description>
</property>

</configuration>

core-site.xml文件

<configuration>
<property>
  <name>fs.default.name</name>
  <value>hdfs://master:54310</value>
  <description>The name of the default file system.  A URI whose
  scheme and authority determine the FileSystem implementation.  The
  uri's scheme determines the config property (fs.SCHEME.impl) naming
  the FileSystem implementation class.  The uri's authority is used to
  determine the host, port, etc. for a filesystem.</description>
</property>

</configuration>

mapred-site.xml文件

<configuration>
<property>
  <name>mapred.job.tracker</name>
  <value>master:54311</value>
  <description>The host and port that the MapReduce job tracker runs
  at.  If "local", then jobs are run in-process as a single map
  and reduce task.
  </description>
</property>

</configuration>

我跟着http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-multi-node-cluster/ .
hadoop 1.2.0 jetty-6.1.26版
添加my hdfs-site.xml之后

<configuration>
<property>
  <name>dfs.replication</name>
    <value>2</value>
      <description>Default block replication.
        The actual number of replications can be specified when the file is created.
          The default is used if replication is not specified in create time.
 </description>
</property>
<property>
<name>dfs.web.ugi</name>
<value>hduser,hadoop</value>
</property>
</configuration>