hadoop2.x的稳定版本，已经发布多时了，散仙一直都用的hadoop1.x的版本，最近有项目用到hadoop2.x，所以就开始折腾hadoop2.x了，在hadoop2.x的版本里，目前最新版本已经到hadoop2.4了，但散仙在这里用的是hadoop2.2.0的版本，为什么用它？因为这是一个稳定的版本，所以相对来说，问题比较少。
散仙在上篇博客，已经讲了如何在编译hadoop2.2.0的64位的版本，如果有不清楚怎么编译，可以参考散仙上篇博文，在这里就不涉及了。

下面，散仙以表格的形式描述下伪分布式安装
系统环境如下：

序号	名称	描述
1	系统环境	Centos6.5
2	JAVA环境	JDK1.7
3	Haoop版本	hadoop2.2.0

安装步骤如下：

序号	步骤
1	解压hadoop，并配置环境变量
2	使用which hadoop命令，测试是否成功
3	配置core-site.xml
4	配置hdfs-site.xml
5	配置yarn-site.xml（非必须，使用默认也可）
6	配置mapred-site.xml
7	配置mapred-env.sh里面的JAVA路径
8	如上的配置完成后，需要新建几个文件夹，来提供HDFS的格式化底层一个是hadoop的tmp文件夹，另外的是namenode和datanode的文件夹，来分别存储各自的信息
9	上面一切完成后，即可执行hadoop namenode -format 进行格式化
10	然后启动伪分布式集群，执行命令sbin/start-all.sh 最后使用JPS查看JAVA进程
11	配置本机的hosts文件，映射主机名信息

下面来详细说下，各个步骤的具体操作：
在这之前，最好配置好本机的SSH无密码登陆操作，避免hadoop进程之间通信时，需要验证。

下面是各个xml文件的配置

Xml代码 @H_301_217@ @H_301_217@

<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://192.168.46.28:9000</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/root/hadoop/tmp</value>
</property>
</configuration>

@H_301_217@

<span style="font-family:Arial;font-size:12px;"><!-- core-site.xml配置 -->
<configuration>
    <property>  
        <name>fs.default.name</name>  
        <value>hdfs://192.168.46.28:9000</value>  
    </property>  
  <property>
    <name>hadoop.tmp.dir</name>
    <value>/root/hadoop/tmp</value>
  </property>

</configuration></span>

Xml代码 @H_301_217@ @H_301_217@

<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
<property>
<name>dfs.namenode.name.dir</name>
<value>/root/hadoop/nddir</value>
</property>
<property>
<name>dfs.datanode.data.dir</name>
<value>/root/hadoop/dddir</value>
</property>
<property>
<name>dfs.permissions</name>
<value>false</value>
</property>
</configuration>

@H_301_217@

<span style="font-family:Arial;font-size:12px;"><!-- hdfs-site.xml配置 -->
 
<configuration>
<property>  
   <name>dfs.replication</name>  
   <value>1</value>  
 </property>  

 <property>  
   <name>dfs.namenode.name.dir</name>  
   <value>/root/hadoop/nddir</value>  
 </property>  


 <property>  
   <name>dfs.datanode.data.dir</name>  
   <value>/root/hadoop/dddir</value>  
 </property>  

<property>  
  <name>dfs.permissions</name>  
  <value>false</value>  
</property>

</configuration>


</span>

Xml代码 @H_301_217@ @H_301_217@

<configuration>
</configuration>

@H_301_217@

<span style="font-family:Arial;font-size:12px;"><!--    yarn-site.xml  不用配置，使用默认属性即可 -->
<configuration>


</configuration>

</span>

Xml代码 @H_301_217@ @H_301_217@

<configuration>
<property>
<name>mapreduce.cluster.temp.dir</name>
<value></value>
<description>Nodescription</description>
<final>true</final>
</property>
<property>
<name>mapreduce.cluster.local.dir</name>
<value></value>
<description>Nodescription</description>
<final>true</final>
</property>
</configuration>

@H_301_217@

<span style="font-family:Arial;font-size:12px;"><!--  mapred-site.xml的配置 -->
<configuration>
<property>  
    <name>mapreduce.cluster.temp.dir</name>  
    <value></value>  
    <description>No description</description>  
    <final>true</final>  
  </property>  
  
  <property>  
    <name>mapreduce.cluster.local.dir</name>  
    <value></value>  
    <description>No description</description>  
    <final>true</final>  
  </property>  
</configuration>
</span>

mapred-env.sh里面的配置

Java代码 @H_301_217@ @H_301_217@

#LicensedtotheApacheSoftwareFoundation(ASF)underoneormore
#contributorlicenseagreements.SeetheNOTICEfiledistributedwith
#thisworkforadditionalinformationregardingcopyrightownership.
#TheASFlicensesthisfiletoYouundertheApacheLicense,Version2.0
#(the"License");youmaynotusethisfileexceptincompliancewith
#theLicense.YoumayobtainacopyoftheLicenseat
#
#http://www.apache.org/licenses/LICENSE-2.0
#
#Unlessrequiredbyapplicablelaworagreedtoinwriting,software
#distributedundertheLicenseisdistributedonan"ASIS"BASIS,
#WITHOUTWARRANTIESORCONDITIONSOFANYKIND,eitherexpressorimplied.
#SeetheLicenseforthespecificlanguagegoverningpermissionsand
#limitationsundertheLicense.
exportJAVA_HOME=/usr/local/jdk
exportHADOOP_JOB_HISTORYSERVER_HEAPSIZE=1000
exportHADOOP_MAPRED_ROOT_LOGGER=INFO,RFA
#exportHADOOP_JOB_HISTORYSERVER_OPTS=
#exportHADOOP_MAPRED_LOG_DIR=""#Wherelogfilesarestored.$HADOOP_MAPRED_HOME/logsbydefault.
#exportHADOOP_JHS_LOGGER=INFO,RFA#HadoopJobSummarylogger.
#exportHADOOP_MAPRED_PID_DIR=#Thepidfilesarestored./tmpbydefault.
#exportHADOOP_MAPRED_IDENT_STRING=#Astringrepresentingthisinstanceofhadoop.$USERbydefault
#exportHADOOP_MAPRED_NICENESS=#Theschedulingpriorityfordaemons.Defaultsto0.

@H_301_217@

<span style="font-family:Arial;font-size:12px;"># Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License,Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,software
# distributed under the License is distributed on an "AS IS" BASIS,# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

export JAVA_HOME=/usr/local/jdk

export HADOOP_JOB_HISTORYSERVER_HEAPSIZE=1000

export HADOOP_MAPRED_ROOT_LOGGER=INFO,RFA

#export HADOOP_JOB_HISTORYSERVER_OPTS=
#export HADOOP_MAPRED_LOG_DIR="" # Where log files are stored.  $HADOOP_MAPRED_HOME/logs by default.
#export HADOOP_JHS_LOGGER=INFO,RFA # Hadoop JobSummary logger.
#export HADOOP_MAPRED_PID_DIR= # The pid files are stored. /tmp by default.
#export HADOOP_MAPRED_IDENT_STRING= #A string representing this instance of hadoop. $USER by default
#export HADOOP_MAPRED_NICENESS= #The scheduling priority for daemons. Defaults to 0.
</span>

然后，建对应的几个文件夹即可，路径都在hadoop2.2的根目录下即可,
然后执行格式化命令bin/hadoop namenode -format即可；

最后使用jps命令，查看进程，如果有以下几个进程名称，就代表部署伪分布式成功

Java代码 @H_301_217@ @H_301_217@

4887NodeManager
4796ResourceManager
4661SecondaryNameNode
4524Datanode
4418NameNode
6122Jps

@H_301_217@

<span style="font-family:Arial;font-size:12px;">4887 NodeManager
4796 ResourceManager
4661 SecondaryNameNode
4524 Datanode
4418 NameNode
6122 Jps</span>

然后，访问界面端口，注意与之前的配置文件里一致，namenode的端口号仍为50070,原来1.x的50030端口，已经没有了，可以访问8088的yarn的端口，来查看，具体的截图如下：

OK，此时，我们已经成功的完成伪分布式的部署，下一步我们要做的，就是跑一个经典的MR程序Hellow World，来测试我们的集群了。