Ubuntu上使用Hadoop 2.x 七 HDFS cluster使用


namenode管理站点

首先namenode有一个web站点，默认端口号是50070， 下面是我的截屏：


至少说明namenode服务启动正常了。


日志

网站上Utilities->Log里面可以看到namenode的日志信息。包括启动的时候Java的版本，参数等等。

也可以看到复制文件t.txt的操作：

2014-03-10 02:43:59,676 INFO org.apache.hadoop.hdfs.StateChange: BLOCK* allocateBlock: /test/t.txt._COPYING_. BP-186292269-192.168.1.71-1394367313744 blk_1073741825_1001{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1, replicas=[ReplicaUnderConstruction[[DISK]DS-4255c8d4-3ca1-4c5a-8184-83310513fb73:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-f988d67f-cdb2-4d57-bd72-0e652527f022:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-5f64aac5-bbff-480a-80b8-fee21719cd31:NORMAL|RBW]]}
2014-03-10 02:44:00,147 INFO BlockStateChange: BLOCK* addStoredBlock: blockMap updated: 192.168.1.75:50010 is added to blk_1073741825_1001{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1, replicas=[ReplicaUnderConstruction[[DISK]DS-4255c8d4-3ca1-4c5a-8184-83310513fb73:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-f988d67f-cdb2-4d57-bd72-0e652527f022:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-5f64aac5-bbff-480a-80b8-fee21719cd31:NORMAL|RBW]]} size 0
2014-03-10 02:44:00,150 INFO BlockStateChange: BLOCK* addStoredBlock: blockMap updated: 192.168.1.73:50010 is added to blk_1073741825_1001{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1, replicas=[ReplicaUnderConstruction[[DISK]DS-4255c8d4-3ca1-4c5a-8184-83310513fb73:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-f988d67f-cdb2-4d57-bd72-0e652527f022:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-5f64aac5-bbff-480a-80b8-fee21719cd31:NORMAL|RBW]]} size 0
2014-03-10 02:44:00,153 INFO BlockStateChange: BLOCK* addStoredBlock: blockMap updated: 192.168.1.74:50010 is added to blk_1073741825_1001{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1, replicas=[ReplicaUnderConstruction[[DISK]DS-4255c8d4-3ca1-4c5a-8184-83310513fb73:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-f988d67f-cdb2-4d57-bd72-0e652527f022:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-5f64aac5-bbff-480a-80b8-fee21719cd31:NORMAL|RBW]]} size 0


为什么只看到datanode1?

原因是datanode2和datanode3中的/etc/hosts中忘记添加配置，加完后再次启动服务，很快网站上看到3个datanode了。


File System Shell

直接在namenode server上运行下面的命令：

hduser@namenode:~$ hdfs dfs -ls hdfs://namenode:9000/
Found 1 items
drwxr-xr-x   - hduser supergroup          0 2014-03-10 02:30 hdfs://namenode:9000/test

可以看到，已经成功创建了test目录。

官方文档参考：http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/FileSystemShell.html

查找帮助的方式

hdfs --help 可以查看总的命令

查看dfs下面具体的命令用法，看下面的例子：

hduser@namenode:~$ hdfs dfs -help cp
-cp [-f] [-p] <src> ... <dst>:	Copy files that match the file pattern <src> to a
		destination.  When copying multiple files, the destination
		must be a directory. Passing -p preserves access and
		modification times, ownership and the mode. Passing -f
		overwrites the destination if it already exists.
复制本地文件到hdfs中，注意src要用file:///前缀

hdfs dfs -cp file:///home/hduser/t.txt hdfs://namenode:9000/test/
这里t.txt是一个本地文件。
hduser@namenode:~$ hdfs dfs -ls hdfs://namenode:9000/test
Found 1 items
-rw-r--r--   3 hduser supergroup          4 2014-03-10 02:44 hdfs://namenode:9000/test/t.txt




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