菜鸟遇到运行hadoop遇到No route to host

谁有遇到过这种情况吗？

2014-05-03 06:46:01,856 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException: Call to hanchar/192.168.100.50:9000 failed on local exception: java.net.NoRouteToHostException: No route to host

没有配置映射

/etc/hosts里面需要配置主机名

我也遇到过这样的情况，不知道是不是一样的问题，我的解决方案如下：
从节点Damenode启动后马上消失，Jps命令再次查看，damenode没有启动；
http://172.16.48.206:50030/jobtracker.jsp查看页面，节点Nodes为0；
2014-04-29 11:50:15,060 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException: Call to sg206/172.16.48.206:9000 fail
ed on local exception: java.net.NoRouteToHostException: No route to host
at org.apache.hadoop.ipc.Client.wrapException(Client.java:1107)
at org.apache.hadoop.ipc.Client.call(Client.java:1075)
.........................
Caused by: java.net.NoRouteToHostException: No route to host
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:701)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:489)

解决方法：关闭防火墙：service iptables stop