2014-03-13 11:10:23,665 INFO org.apache.Hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:24,667 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:25,667 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:26,669 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 3 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:27,670 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 4 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:28,671 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 5 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:29,672 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 6 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:30,674 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 7 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:31,675 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 8 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:32,676 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Linux-hadoop-38/10.10.208.38:9000. Already tried 9 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-13 11:10:32,677 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Problem connecting to server: Linux-hadoop-38/10.10.208.38:9000
解决办法:
1、ping Linux-hadoop-38能通,telnet Linux-hadoop-38 9000不能通，说明开启了防火墙
2、去Linux-hadoop-38主机关闭防火墙/etc/init.d/iptables stop，显示:
iptables：清除防火墙规则：[确定]
iptables：将链设置为政策 ACCEPT：filter [确定]
iptables：正在卸载模块：[确定]
3、重启
异常二：
2014-03-13 11:26:30,788 FATAL org.apache.hadoop.hdfs.server.datanode.DataNode: Initialization failed for block pool Block pool BP-1257313099-10.10.208.38-1394679083528 (storage id DS-743638901-127.0.0.1-50010-1394616048958) service to Linux-hadoop-38/10.10.208.38:9000
java.io.IOException: Incompatible clusterIDs in /usr/local/hadoop/tmp/dfs/data: namenode clusterID = CID-8e201022-6faa-440a-b61c-290e4ccfb006; datanode clusterID = clustername
at org.apache.hadoop.hdfs.server.datanode.DataStorage.doTransition(DataStorage.java:391)
at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:191)
at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:219)
at org.apache.hadoop.hdfs.server.datanode.DataNode.initStorage(DataNode.java:916)
at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:887)
at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:309)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:218)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:660)
at java.lang.Thread.run(Thread.java:662)
解决办法:
1、在hdfs-site.xml配置文件中，配置了dfs.namenode.name.dir，在master中,该配置的目录下有个current文件夹，里面有个VERSION文件,内容如下:
#Thu Mar 13 10:51:23 CST 2014
namespaceID=1615021223
clusterID=CID-8e201022-6faa-440a-b61c-290e4ccfb006
cTime=0
storageType=NAME_NODE
blockpoolID=BP-1257313099-10.10.208.38-1394679083528
layoutVersion=-40
2、在core-site.xml配置文件中，配置了hadoop.tmp.dir，在slave中,该配置的目录下有个dfs/data/current目录，里面也有一个VERSION文件，内容
#Wed Mar 12 17:23:04 CST 2014
storageID=DS-414973036-10.10.208.54-50010-1394616184818
clusterID=clustername
cTime=0
storageType=DATA_NODE
layoutVersion=-40
3、一目了然，两个内容不一样，导致的。删除slave中的错误内容，重启，搞定！
异常三：