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_01
export HADOOP_HOME=//data/software/hadoop-1.0.3
export 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]# ls
capacity-scheduler.xml  hadoop-env.sh~              mapred-site.xml
configuration.xsl       hadoop-metrics2.properties  masters
core-site.xml           hadoop-policy.xml           slaves
core-site.xml~          hdfs-site.xml               ssl-client.xml.example
fair-scheduler.xml      log4j.properties            ssl-server.xml.example
hadoop-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 dsa
Generating 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 [e-mail]

连接本机，测试无需输入密码成功：

[root@SC-026 conf]# ssh 192.168.15.45
Last 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 -format
12/08/29 12:43:55 INFO namenode.NameNode: STARTUP_MSG: 
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG:   host = SC-026.cfind.com/192.168.15.45
STARTUP_MSG:   args = [-format]
STARTUP_MSG:   version = 1.0.3
STARTUP_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-bit
12/08/29 12:43:56 INFO util.GSet: 2% max memory = 17.77875 MB
12/08/29 12:43:56 INFO util.GSet: capacity      = 2^21 = 2097152 entries
12/08/29 12:43:56 INFO util.GSet: recommended=2097152, actual=2097152
12/08/29 12:43:56 INFO namenode.FSNamesystem: fsOwner=root
12/08/29 12:43:56 INFO namenode.FSNamesystem: supergroup=supergroup
12/08/29 12:43:56 INFO namenode.FSNamesystem: isPermissionEnabled=true
12/08/29 12:43:56 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=100
12/08/29 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.out
localhost: starting datanode, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-datanode-SC-026.cfind.com.out
localhost: starting secondarynamenode, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-secondarynamenode-SC-026.cfind.com.out
starting jobtracker, logging to /data/software/hadoop-1.0.3/libexec/../logs/hadoop-root-jobtracker-SC-026.cfind.com.out
localhost: 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]# jps
6247 JobTracker
3572 org.eclipse.equinox.launcher_1.2.0.v20110502.jar
5902 NameNode
6161 SecondaryNameNode
6396 TaskTracker
6467 Jps
6029 DataNode

终止进程：

[root@SC-026 bin]# stop-all.sh 
stopping jobtracker
localhost: stopping tasktracker
stopping namenode
localhost: stopping datanode
localhost: 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。