Linux（CentOS）下伪分布模式安装Hadoop
一、下载
下载地址：http://apache.etoak.com/hadoop/common/
打开会发现不同版本，我这里选择的是：hadoop-1.0.3.tar.gz
下载位置到：/data/software
二、安装
利用命令tar解压缩安装，解压结果如下：
[root@SC-026 ~]# cd /data/software/[root@SC-026 software]# tar xvf hadoop-1.0.3.tar.gz
如果JAVA_HOME环境变量已经指向一个java安装，则不需要进行配置。
[root@SC-026 software]# echo $JAVA_HOME/usr/java/jdk1.7.0_01
否则，编辑../conf/hadoop-env.sh文件来设置JAVA_HOME变量
[root@SC-026 software]# cd hadoop-1.0.3/conf[root@SC-026 conf]# vim hadoop-env.sh
本机中是如下编辑：
export JAVA_HOME=/usr/java/jdk1.7.0_01export HADOOP_HOME=//data/software/hadoop-1.0.3export PATH=$PATH:$HADOOP_HOME/bin
:wq保存，退出。
三、配置
Hadoop的各个组件均可利用xml文件配置。
core-site.xml:用于配置Common组件的属性；
hdfs-site.xml:用于配置HDFS属性；
mapred-site.xml:用于配置MapReduce属性。
这些配置文件都在以下路径中：
[root@SC-026 conf]# lscapacity-scheduler.xml hadoop-env.sh~ mapred-site.xmlconfiguration.xsl hadoop-metrics2.properties masterscore-site.xml hadoop-policy.xml slavescore-site.xml~ hdfs-site.xml ssl-client.xml.examplefair-scheduler.xml log4j.properties ssl-server.xml.examplehadoop-env.sh mapred-queue-acls.xml taskcontroller.cfg
通过vim依次打开3个文件，配置如下：
[root@SC-026 conf]# vim core-site.xml<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="configuration.xsl"?><!-- Put site-specific property overrides in this file. --><configuration> <property> <name>fs.default.name</name> <value>hdfs://localhost</value> </property></configuration>
[root@SC-026 conf]# vim hdfs-site.xml <?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="configuration.xsl"?><!-- Put site-specific property overrides in this file. --><configuration> <property> <name>dfs.replication</name> <value>1</value> </property></configuration>
[root@SC-026 conf]# vim mapred-site.xml <?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="configuration.xsl"?><!-- Put site-specific property overrides in this file. --><configuration> <property> <name>mapred.job.tracker</name> <value>localhost:8021</value> </property></configuration>
四、配置SSH
如本机中未安装，直接利用以下命令安装：
[root@SC-026 conf]#yum install ssh
启用无密码登录，输入以下命令直接回车即可：
[root@SC-026 conf]# ssh-keygen -t dsaGenerating public/private dsa key pair.Enter file in which to save the key (/root/.ssh/id_dsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /root/.ssh/id_dsa.Your public key has been saved in /root/.ssh/id_dsa.pub.The key fingerprint is:4d:f1:da:e9:a4:80:4f:c2:32:d5:f8:94:55:32:70:cb root@SC-026.cfind.com
连接本机，测试无需输入密码成功：
[root@SC-026 conf]# ssh 192.168.15.45Last login: Thu Jun 14 08:37:05 2012
五、格式化HDFS文件系统
[root@SC-026 conf]# cd ../bin[root@SC-026 bin]# hadoop namenode -format12/08/29 12:43:55 INFO namenode.NameNode: STARTUP_MSG: /************************************************************STARTUP_MSG: Starting NameNodeSTARTUP_MSG: host = SC-026.cfind.com/192.168.15.45STARTUP_MSG: args = [-format]STARTUP_MSG: version = 1.0.3STARTUP_MSG: build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.0 -r 1335192; compiled by 'hortonfo' on Tue May 8 20:31:25 UTC 2012************************************************************/12/08/29 12:43:56 INFO util.GSet: VM type = 64-bit12/08/29 12:43:56 INFO util.GSet: 2% max memory = 17.77875 MB12/08/29 12:43:56 INFO util.GSet: capacity = 2^21 = 2097152 entries12/08/29 12:43:56 INFO util.GSet: recommended=2097152, actual=209715212/08/29 12:43:56 INFO namenode.FSNamesystem: fsOwner=root12/08/29 12:43:56 INFO namenode.FSNamesystem: supergroup=supergroup12/08/29 12:43:56 INFO namenode.FSNamesystem: isPermissionEnabled=true12/08/29 12:43:56 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=10012/08/29 12:43:56 INFO namenode.FSNamesystem: isAccessTokenEnabled=false accessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s)12/08/29 12:43:56 INFO namenode.NameNode: Caching file names occuring more than 10 times 12/08/29 12:43:56 INFO common.Storage: Image file of size 110 saved in 0 seconds.12/08/29 12:43:56 INFO common.Storage: Storage directory [color=red]/tmp/hadoop-root/dfs/name has been successfully formatted.[/color]12/08/29 12:43:56 INFO namenode.NameNode: SHUTDOWN_MSG: /************************************************************SHUTDOWN_MSG: Shutting down NameNode at SC-026.cfind.com/192.168.15.45
六、启动和终止守护进程
启动进程：
[root@SC-026 bin]# start-all.sh starting namenode, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-namenode-SC-026.cfind.com.outlocalhost: starting datanode, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-datanode-SC-026.cfind.com.outlocalhost: starting secondarynamenode, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-secondarynamenode-SC-026.cfind.com.outstarting jobtracker, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-jobtracker-SC-026.cfind.com.outlocalhost: starting tasktracker, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-tasktracker-SC-026.cfind.com.out
这里启动三个守护进程：namenode, senconaryNameNode, DataNode，用命令jps可以查看进程是否成功？
[root@SC-026 bin]# jps6247 JobTracker3572 org.eclipse.equinox.launcher_1.2.0.v20110502.jar5902 NameNode6161 SecondaryNameNode6396 TaskTracker6467 Jps6029 DataNode
终止进程：
[root@SC-026 bin]# stop-all.sh stopping jobtrackerlocalhost: stopping tasktrackerstopping namenodelocalhost: stopping datanodelocalhost: stopping secondarynamenode
以上配置成功后，在浏览器中输入：http://localhost:50030 会有以下页面：
输入：http://localhost:50070 会有以下页面：
在上述安装过程中，碰到不少问题，下一篇文章会统一说明解决。