Hadoop基本命令

==============================Master=========================

1. 查看Datanode的运行情况
   • 命令：hadoop dfsadmin -repor
   • 网页查看：http://192.168.242.128:50030/jobtracker.jsp
   • http://192.168.242.128:50070/dfshealth.jsp

2. 删除节点：

   • 配置hdfs-site
     

     <property>  　　<name>dfs.hosts.exclude</name>  　　<value>/data/soft/hadoop/conf/excludes</value>  　　<description>Names a file that contains a list of hosts that are   　　not permitted to connect to the namenode.  The full pathname of the   　　file must be specified.  If the value is empty, no hosts are   　　excluded.</description></property>

   • 添加到中dfs.hosts.exclude，设置不需要连接的机器
   • 强制重新加载配置：hadoop dfsadmin -refreshNodes 

================================HDFS=======================

• hadoop fs -mkdir input
• hadoop fs -ls
• hadoop jar /usr/hadoop/hadoop-examples-1.2.1.jar wordcount input output
  

============================Datanode==================

1. 重启节点：
   • 现在节点分别启动：hadoop-daemon.sh start datanode；hadoop-daemon.sh start tasktracker
   • 均衡block：start-balancer.sh