今天再测试的时候报错了

[root@linuxmain hadoop]# bin/hadoop jar hdfs3.jar com.dragon.test.CopyToHDFS
Java HotSpot(TM) Client VM warning: You have loaded library /usr/hadoop/lib/native/libhadoop.so.1.0.0 which might have disabled stack guard. The VM will try to fix the stack guard now.
It's highly recommended that you fix the library with 'execstack -c <libfile>', or link it with '-z noexecstack'.
14/12/02 19:23:27 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
14/12/02 19:23:28 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.io.IOException: Bad connect ack with firstBadLink as 192.168.1.218:50010
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.createBlockOutputStream(DFSOutputStream.java:1377)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1281)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:526)
14/12/02 19:23:28 INFO hdfs.DFSClient: Abandoning BP-1405147126-192.168.1.216-1417571791797:blk_1073741834_1010
14/12/02 19:23:28 INFO hdfs.DFSClient: Excluding datanode 192.168.1.218:50010
14/12/02 19:23:28 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.io.IOException: Bad connect ack with firstBadLink as 192.168.1.217:50010
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.createBlockOutputStream(DFSOutputStream.java:1377)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1281)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:526)
14/12/02 19:23:28 INFO hdfs.DFSClient: Abandoning BP-1405147126-192.168.1.216-1417571791797:blk_1073741835_1011
14/12/02 19:23:28 INFO hdfs.DFSClient: Excluding datanode 192.168.1.217:50010
意思就是坏的连接 网络未通你把防火墙一关就好了。
linux有操作界面可以根据界面关闭。也可以使用命令关闭
使用命令关闭:
1) 重启后生效 
开启: chkconfig iptables on
关闭: chkconfig iptables off

2) 即时生效,重启后失效
开启: service iptables start
关闭: service iptables stop

hadoop报错java.io.IOException: Bad connect ack with firstBadLink as 192.168.1.218:50010_hadoop