本节主要内容：
A：主机名规划设置
B：Java环境设置
C：CDH源配置
1.系统环境：
OS：CentOS Linux release 7.5.1804 (Core)
CPU：2核心
Memory：1GB
运行用户：root
JDK版本：1.8.0_252
Hadoop版本：cdh5.16.2
2.集群各节点角色规划为：
172.26.37.245 node1.hadoop.com
172.26.37.246 node2.hadoop.com
172.26.37.247 node3.hadoop.com
172.26.37.248 node4.hadoop.com
3.hosts更新
# vi /etc/hosts
增加以下内容
172.26.37.245 node1.hadoop.com
172.26.37.246 node2.hadoop.com
172.26.37.247 node3.hadoop.com
172.26.37.248 node4.hadoop.com
4.分别修改hostname
# hostname node1.hadoop.com
# hostname node2.hadoop.com
# hostname node3.hadoop.com
# hostname node4.hadoop.com
5.更新最新JAVA环境
# yum update java
6.设置Java环境变量
# vim /etc/profile
增加以下内容
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.252.b09-2.el7_8.x86_64/jre
export PATH=$JAVA_HOME/bin:$PATH
# source /etc/profile
# java -version
openjdk version "1.8.0_252"
OpenJDK Runtime Environment (build 1.8.0_252-b09)
OpenJDK 64-Bit Server VM (build 25.252-b09, mixed mode)
7.配置CDH源
# wget http://archive.cloudera.com/cdh5/one-click-install/redhat/7/x86_64/cloudera-cdh-5-0.x86_64.rpm
# rpm -i cloudera-cdh-5-0.x86_64.rpm
# ll /etc/yum.repos.d/cloudera-cdh5.repo
Hadoop生态圈基本的实验环境就准备好了！！
