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 / 上傳文件到遠程目錄(/)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

緣由：

一、某個節點機器忽然開啓防火牆，致使不能鏈接

二、強制kill掉某個節點（聽說）

三、某個機器直接當掉，豈不是完蛋了？數據冗餘容災的設計幹什麼吃的？（推測）

解決方法：

root用戶關閉防火牆  service iptables stop

多是某個節點由於重啓把iptables又起來了，

能夠用chkconfig iptables off解決重啓帶來的問題，

不重啓的話用service iptables stop關掉。