在FinalShell中安装Hadoop3的详细步骤是什么？
# FinalShell 连接 CentOS7 安装 Hadoop3.3.6 超详细完整步骤
全程在 **FinalShell** 操作，复制命令直接运行，适配：CentOS7 + Hadoop3.3.6 + JDK8，伪分布式/完全分布式通用。
---
# 前期准备（FinalShell 内全部执行）
## 1. 关闭防火墙 & SELinux
```bash
# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
# 关闭SELinux
setenforce 0
sed -i 's/^SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
```
## 2. 安装依赖
```bash
yum install -y wget net-tools vim openssh-clients
```
---
# 第一步：安装 JDK8（Hadoop 必备）
## 1. 一键安装 OpenJDK8
```bash
yum install -y java-1.8.0-openjdk-devel
```
## 2. 查看JDK真实路径
```bash
readlink -f $(which java)
```
示例路径：
`/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.402-0.b06.el7_9.x86_64`
## 3. 配置全局环境变量
```bash
vim /etc/profile
```
文件最底部添加：
```sh
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.402-0.b06.el7_9.x86_64
export PATH=$JAVA_HOME/bin:$PATH
```
保存退出：`ESC` → 输入 `:wq` 回车
## 4. 生效配置
```bash
source /etc/profile
java -version
```
显示 `1.8.0` 即为成功。
---
# 第二步：配置主机名 + hosts映射
## 1. 设置主机名
```bash
hostnamectl set-hostname hadoop-master
```
## 2. 配置hosts
```bash
vim /etc/hosts
```
添加一行（写你自己虚拟机IP）：
```
192.168.122.130 hadoop-master
```
---
# 第三步：配置 SSH 免密登录
```bash
# 生成密钥 全部回车
ssh-keygen -t rsa
# 写入免密文件
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
# 测试免密
ssh hadoop-master date
```
---
# 第四步：下载 & 解压 Hadoop3.3.6
## 1. 进入 /opt 目录
```bash
cd /opt
```
## 2. 清华镜像下载 Hadoop
```bash
wget https://mirrors.tuna.tsinghua.edu.cn/apache/hadoop/common/hadoop-3.3.6/hadoop-3.3.6.tar.gz
```
## 3. 解压 + 重命名
```bash
tar -zxvf hadoop-3.3.6.tar.gz
mv hadoop-3.3.6 hadoop
```
## 4. Hadoop 环境变量配置
```bash
vim /etc/profile
```
追加以下内容：
```sh
export HADOOP_HOME=/opt/hadoop
export HADOOP_CONF_DIR=$HADOOP_HOME/etc/hadoop
export HADOOP_PATH=$HADOOP_HOME/bin:$HADOOP_HOME/sbin
export PATH=$PATH:$HADOOP_PATH
```
生效：
```bash
source /etc/profile
# 验证
hadoop version
```
---
# 第五步：修改 Hadoop 核心配置文件
配置目录：`/opt/hadoop/etc/hadoop`
## 1. 配置 hadoop-env.sh
```bash
vim /opt/hadoop/etc/hadoop/hadoop-env.sh
```
末尾添加：
```sh
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.402-0.b06.el7_9.x86_64
export HDFS_NAMENODE_USER=root
export HDFS_DATANODE_USER=root
export HDFS_SECONDARYNAMENODE_USER=root
export YARN_RESOURCEMANAGER_USER=root
export YARN_NODEMANAGER_USER=root
```
## 2. 配置 core-site.xml
```bash
vim /opt/hadoop/etc/hadoop/core-site.xml
```
替换全部内容：
```xml
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://hadoop-master:9000</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/opt/hadoop/tmp</value>
</property>
<property>
<name>hadoop.proxyuser.root.hosts</name>
<value>*</value>
</property>
<property>
<name>hadoop.proxyuser.root.groups</name>
<value>*</value>
</property>
</configuration>
```
## 3. 配置 hdfs-site.xml
```bash
vim /opt/hadoop/etc/hadoop/hdfs-site.xml
```
```xml
<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
<property>
<name>dfs.permissions.enabled</name>
<value>false</value>
</property>
</configuration>
```
## 4. 配置 mapred-site.xml
```bash
vim /opt/hadoop/etc/hadoop/mapred-site.xml
```
```xml
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
<property>
<name>yarn.app.mapreduce.am.env</name>
<value>HADOOP_MAPRED_HOME=${HADOOP_HOME}</value>
</property>
<property>
<name>mapreduce.map.env</name>
<value>HADOOP_MAPRED_HOME=${HADOOP_HOME}</value>
</property>
<property>
<name>mapreduce.reduce.env</name>
<value>HADOOP_MAPRED_HOME=${HADOOP_HOME}</value>
</property>
</configuration>
```
## 5. 配置 yarn-site.xml
```bash
vim /opt/hadoop/etc/hadoop/yarn-site.xml
```
```xml
<configuration>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.resourcemanager.hostname</name>
<value>hadoop-master</value>
</property>
</configuration>
```
## 6. 修改 workers
```bash
vim /opt/hadoop/etc/hadoop/workers
```
清空原有内容，写入：
```
hadoop-master
```
---
# 第六步：初始化 & 启动 Hadoop
## 1. 格式化 NameNode（**只执行一次**）
```bash
hdfs namenode -format
```
## 2. 启动 HDFS
```bash
start-dfs.sh
```
## 3. 启动 YARN
```bash
start-yarn.sh
```
## 4. 查看进程
```bash
jps
```
正常进程：
- NameNode
- DataNode
- SecondaryNameNode
- ResourceManager
- NodeManager
---
# 第七步：访问 Web 页面
虚拟机放行端口或关闭防火墙后，浏览器打开：
- HDFS：`http://虚拟机IP:9870`
- YARN：`http://虚拟机IP:8088`
---
# 常用停止命令
```bash
stop-dfs.sh
stop-yarn.sh
