如何搭建hadoop集群
今天决定重新搭建hadoop集群，如果是新手看这篇文章一定不要觉得很难，你只需要耐心和细心就ok了
准备工作
1.判断机器上是否有ssh服务，
[jinyang@OnlyKing Desktop]$ ssh -verison
OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010
Bad escape character 'rison'.
我的系统自带的，所以不用装了。
2.判断机器上是否有JDK
[jinyang@OnlyKing Desktop]$ java -version
java version "1.6.0_24"
OpenJDK Runtime Environment (IcedTea6 1.11.1) (rhel-1.45.1.11.1.el6-i386)
OpenJDK Server VM (build 20.0-b12, mixed mode)
[jinyang@OnlyKing Desktop]$ javac -version
javac 1.6.0_24
如果是系统自带的JDK，最好重装一下。http://blog.csdn.net/a15039096218/article/details/7378293
进入主题
1.下载和安装hadoop，我下载的是hadoop-0.20.2.tar.gz
解压文件：[root@OnlyKing Downloads]# tar -zxvf hadoop-0.20.2.tar.gz
移动文件：[root@OnlyKing Downloads]# mv hadoop-0.20.2 /usr/local/
安装文件：[root@OnlyKing Downloads]# ln -s hadoop-0.20.2 hadoop
2.修改环境变量
[root@OnlyKing local]#vi /etc/profile
在文件的下面添加，不能直接在文件的上面添加
export HADOOP_HOME=/usr/local/hadoop
export PATH=$PATH:$HADOOP_HOME/bin
[root@OnlyKing local]#. /etc/profile
[root@OnlyKing local]# vi /usr/local/hadoop/conf/hadoop.env.sh(配置JAVA_HOME)
[root@OnlyKing Desktop]# hadoop version
Hadoop 0.20.2
Subversion https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20 -r 911707
Compiled by chrisdo on Fri Feb 19 08:07:34 UTC 2010
压轴大戏
1.NameNode配置
[hadoop@hadoop1 ~]# vi /etc/hosts
192.168.127.145 hadoop1
192.168.127.146 hadoop2
192.168.127.147 hadoop3
192.168.127.148 hadoop4
[root@OnlyKing conf]# vi core-site.xml
<property> <name>dfs.replication</name> <value>3</value> </property> <property> <name>dfs.data.dir</name> <value>/home/hadoop/data</value> </property> <property> <name>hadoop.tmp.dir</name> <value>/usr/local/hadoop/tmp/</value> </property><configuration>
