hadoop 在启动的时候报下面的错误：
2012-09-18 13:42:38,901 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 0 time(s).
2012-09-18 13:42:39,904 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 1 time(s).
2012-09-18 13:42:40,906 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 2 time(s).
2012-09-18 13:42:41,908 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 3 time(s).
2012-09-18 13:42:42,910 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 4 time(s).
2012-09-18 13:42:43,913 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 5 time(s).
2012-09-18 13:42:44,916 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 6 time(s).
2012-09-18 13:42:45,919 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 7 time(s).
2012-09-18 13:42:46,922 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 8 time(s).
2012-09-18 13:42:47,925 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: master/192.168.1.240:9000. Already tried 9 time(s).
所有的配置参数 检查了好几遍了 都没有问题。
/etc/hosts 也没有问题。
解决办法：
安装目录： /app/hadoop/
cd /app/hadoop/bin 下面执行
1.关闭所有的节点：
./stop-all.sh
2.namenode格式化
hadoop namenode -format
注意： 判断是否re_format filesystem 的时候 Y/N 一定要大写的 Y!!!
3.开启所有的节点：
./start-all.sh
格式化之后基本上都是能够启动的 除非你的配置错了、