hadoop集群在线添加datanode

1,按照如下方法配置安装hadoop服务器，完成准备配置
http://blog.csdn.net/hijk139/article/details/8307343

2，修改master主机的slave配置，添加所需的dataname的主机名或者IP地址

3，启动datanode节点上的相关进程
$ cd path/to/hadoop
$ bin/hadoop-daemon.sh start datanode
$ bin/hadoop-daemon.sh start tasktracker

4，验证

进程存在jps

[hadoop@slog1 tmp]$ jps
13838 Jps
9163 TaskTracker
30971 Application
8230 DataNode
20733 SecondaryNameNode
20538 NameNode
20865 JobTracker

查看更详细的节点信息

[hadoop@slog1 tmp]$  hadoop dfsadmin -report
Warning: $HADOOP_HOME is deprecated.

Configured Capacity: 34803168522240 (31.65 TB)
Present Capacity: 17580382365257 (15.99 TB)
DFS Remaining: 9858973999104 (8.97 TB)
DFS Used: 7721408366153 (7.02 TB)
DFS Used%: 43.92%
Under replicated blocks: 1599
Blocks with corrupt replicas: 0
Missing blocks: 0

-------------------------------------------------
Datanodes available: 3 (3 total, 0 dead)

Name:  192.168.0.6:50010
Decommission Status : Normal
Configured Capacity: 15853401194496 (14.42 TB)
DFS Used: 3860704572802 (3.51 TB)
Non DFS Used: 8530007943806 (7.76 TB)
DFS Remaining: 3462688677888(3.15 TB)
DFS Used%: 24.35%
DFS Remaining%: 21.84%
Last contact: Mon Mar 31 17:11:08 CST 2014


Name:  192.168.0.1:50010
Decommission Status : Normal
Configured Capacity: 15853401194496 (14.42 TB)
DFS Used: 3860162642063 (3.51 TB)
Non DFS Used: 8529116761969 (7.76 TB)
DFS Remaining: 3464121790464(3.15 TB)
DFS Used%: 24.35%
DFS Remaining%: 21.85%
Last contact: Mon Mar 31 17:11:07 CST 2014


Name:  192.168.0.5:50010
Decommission Status : Normal
Configured Capacity: 3096366133248 (2.82 TB)
DFS Used: 541151288 (516.08 MB)
Non DFS Used: 163661451208 (152.42 GB)
DFS Remaining: 2932163530752(2.67 TB)
DFS Used%: 0.02%
DFS Remaining%: 94.7%
Last contact: Mon Mar 31 17:11:08 CST 2014

参考文档
http://wiki.apache.org/hadoop/FAQ#I_have_a_new_node_I_want_to_add_to_a_running_Hadoop_cluster.3B_how_do_I_start_services_on_just_one_node.3F