centos 7 下Hadoop 2.7.2 伪分布式安装,安装jdk，免密匙登录，配置mapreduce，配置YARN。详细步骤如下：

1.0 安装JDK

1.1 查看是否安装了openjdk

[lei@bogon ~]$ java -version
openjdk version "1.8.0_65"
OpenJDK Runtime Environment (build 1.8.0_65-b17)
OpenJDK 64-Bit Server VM (build 25.65-b01, mixed mode)

1.2 查看openjdk源

[lei@bogon ~]$ rpm -qa | grep java
java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
tzdata-java-2015g-1.el7.noarch
python-javapackages-3.4.1-11.el7.noarch
javapackages-tools-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64
java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64

1.3 需root登录

[lei@bogon ~]$ rpm -e --nodeps tzdata-java-2015g-1.el7.noarch
错误：can't create 事务 lock on /var/lib/rpm/.rpm.lock (权限不够)
[lei@bogon ~]$ su
密码：

1.4 依次删除OPENJDK

[root@bogon lei]# rpm -e --nodeps java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
[root@bogon lei]# rpm -e --nodeps tzdata-java-2015g-1.el7.noarch
[root@bogon lei]# rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
[root@bogon lei]# rpm -e --nodeps java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64
[root@bogon lei]# rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64

1.5 将下载JDK后缀为.tar.gz解压缩至/opt路径下

[root@bogon lei]# tar -zxf/home/lei/桌面/jdk-8u77-linux-x64.tar.gz -C /opt

1.6 配置JDK环境变量

[root@bogon lei]# vim /etc/profile.d/java.sh

输入以下内容

JAVA_HOME=/opt/jdk1.8.0_77
JRE_HOME=/opt/jdk1.8.0_77/jre
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib:$CLASSPATH
PATH=$JAVA_HOME/bin:$PATH

1. 8使变量生效

source /etc/profile.d/java.sh

2.0 ssh 免密匙登录

是否可以免密匙登录

[root@bogon lei]# ssh localhost
The authenticity of host 'localhost (::1)' can't be established.
ECDSA key fingerprint is 7b:10:e3:b5:ea:7d:29:be:77:83:1c:c0:1d:85:de:ba.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts.
[root@localhost's password:
Last login: Sat Apr  2 22:32:44 2016

配置免密匙登录

[root@bogon ~]# ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa
Generating public/private dsa key pair.
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:
e0:ba:3c:c5:73:dd:f0:39:51:ad:87:4b:dc:32:46:83 root@bogon
The key's randomart image is:
+--[ DSA 1024]----+
|             . . |
|            E + .|
|      .      + = |
|     . .  . . O o|
|     .. S. + = = |
|     .+ . . = .  |
|    .. o     .   |
|   ...           |
|    o.           |
+-----------------+

[root@bogon ~]# cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys
[root@bogon ~]# chmod 0600 ~/.ssh/authorized_keys

再次登录，即可免密匙

[root@bogon ~]# ssh localhost
Last login: Sat Apr  2 22:51:41 2016 from localhost

3.0 安装Hadoop

3.0.1解压Hadoop至/opt路径下

tar -zxf /home/lei/桌面/hadoop-2.7.2.tar.gz -C /opt

3.0.2配置Hadoop环境变量

vim /etc/profile.d/hadoop.sh

输入以下内容

export HADOOP_HOME=/opt/hadoop-2.7.2
export HADOOP_PREFIX=/opt/hadoop-2.7.2

使变量生效

source /etc/profile.d/hadoop.sh

3.0.3进入已经解压的Hadoop路径下

[root@bogon ~]# cd /opt/hadoop-2.7.2

3.0.4 修改hadoop-env.sh 增加JAVA_HOME路径

[root@bogon hadoop-2.7.2]# vim etc/hadoop/hadoop-env.sh

增加如下代码

export JAVA_HOME=/opt/

3.0.5 运行命令可看到Hadoop支持的命令

[root@bogon hadoop-2.7.2]# bin/hadoop

3.1 配置Mapreduce

3.1.1 编辑core-site.xml

[root@bogon hadoop-2.7.2]# vim etc/hadoop/core-site.xml
<configuration><property><name>fs.defaultFS</name><value>hdfs://localhost:9000</value></property>
</configuration>

3.1.2 编辑hdfs-site.xml

[root@bogon hadoop-2.7.2]# vim etc/hadoop/hdfs-site.xml
<configuration><property><name>dfs.replication</name><value>1</value></property>
</configuration>

3.1.3 格式化

[root@bogon hadoop-2.7.2]# bin/hdfs namenode -format

省略N行
16/04/02 22:54:15 INFO common.Storage: Storage directory /tmp/hadoop-root/dfs/name has been successfully formatted./************************************************************
SHUTDOWN_MSG: Shutting down NameNode at bogon/221.192.153.42
************************************************************/

3.1.4 开启mapreduce

[root@bogon hadoop-2.7.2]# sbin/start-dfs.sh

3.1.5 访问http://localhost:50070/

如图

3.1.6 运行mapreduce案例

[root@bogon hadoop-2.7.2]# bin/hdfs dfs -mkdir /user

[root@bogon hadoop-2.7.2]# bin/hdfs dfs -mkdir /user/lei

### 如果出现没有input错误
[root@bogon hadoop-2.7.2]# bin/hdfs dfs -put etc/hadoop input
put: `input': No such file or directory
### 手动创建
[root@bogon hadoop-2.7.2]# bin/hadoop fs -mkdir -p input

[root@bogon hadoop-2.7.2]# bin/hdfs dfs -put etc/hadoop input

[root@bogon hadoop-2.7.2]# bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar grep input output 'dfs[a-z.]+'

3.1.7 查看文件

[root@bogon hadoop-2.7.2]# bin/hadoop dfs -ls
DEPRECATED: Use of this script to execute hdfs command is deprecated.
Instead use the hdfs command for it.
Found 2 items
drwxr-xr-x   - root supergroup          0 2016-04-02 23:39 input
drwxr-xr-x   - root supergroup          0 2016-04-02 23:43 output

3.1.8 停止mapreduce

[root@bogon hadoop-2.7.2]#sbin/start-dfs.sh

mapreduce配置完成

3.2 YARN配置

3.2.1 配置mapred-site.xml

[root@bogon hadoop-2.7.2]# mv etc/hadoop/mapred-site.xml.template etc/hadoop/mapred-site.xml

[root@bogon hadoop-2.7.2]# vim etc/hadoop/mapred-site.xml<configuration><property><name>mapreduce.framework.name</name><value>yarn</value></property>
</configuration>

3.2.2配置yarn-site.xml

[root@bogon hadoop-2.7.2]# vim etc/hadoop/yarn-site.xml<configuration><property><name>yarn.nodemanager.aux-services</name><value>mapreduce_shuffle</value></property>
</configuration>

[root@bogon hadoop-2.7.2]# sbin/start-yarn.sh

3.2.3 稍等片刻启动完毕后 打开http://localhost:8088/

如图

Hadoop伪分布式安装完成