java.io.IOException: Bad connect ack with firstBad

[hadoop @master ~]$ touch bigfile.tar
[hadoop @master ~]$ cat hadoop-2.5.2.tar.gz >> bigfile.tar
[hadoop @master ~]$ touch bigfile.tarcat
[hadoop @master ~]$ 
[hadoop @master ~]$ 
[hadoop@master ~]$ cat hadoop-2.5.2.tar.gz >> bigfile.tar
[hadoop@master ~]$ hadoop fs -put bigfile.tar / 上传文件到远程目录(/)下
15/12/03 00:57:22 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
15/12/03 00:57:26 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.io.IOException: Bad connect ack with firstBadLink as 192.168.209.102:50010
        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$DataStreamer.run(DFSOutputStream.java:526)
15/12/03 00:57:26 INFO hdfs.DFSClient: Abandoning BP-2062059271-192.168.209.100-1448384244888:blk_1073741864_1040
15/12/03 00:57:26 INFO hdfs.DFSClient: Excluding datanode 192.168.209.102:50010
15/12/03 00:57:26 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.io.IOException: Bad connect ack with firstBadLink as 192.168.209.101:50010
        at org.apache.hadoop.hdfs.DFSOutputStream$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)
15/12/03 00:57:26 INFO hdfs.DFSClient: Abandoning BP-2062059271-192.168.209.100-1448384244888:blk_1073741865_1041

15/12/03 00:57:26 INFO hdfs.DFSClient: Excluding datanode 192.168.209.101:50010

缘由：

一、某个节点机器忽然开启防火墙，致使不能链接

二、强制kill掉某个节点（听说）

三、某个机器直接当掉，岂不是完蛋了？数据冗余容灾的设计干什么吃的？（推测）

解决方法：

root用户关闭防火墙  service iptables stop

多是某个节点由于重启把iptables又起来了，

能够用chkconfig iptables off解决重启带来的问题，

不重启的话用service iptables stop关掉。