A complete hadoop installation, it is recommended to collect

Introduction

Previously, my back-end partner sent a private message. I want to know about the stand-alone environment installation of hadoop. Today, I arranged it for everyone. Not much nonsense, I will directly send dry goods.

Precondition
Configure SSH password-free login
Hadoop (HDFS) environment construction
Hadoop (YARN) environment construction

1, precondition

The operation of Hadoop depends on JDK, which needs to be installed in advance. See the installation steps:

1.1 Download and unzip

Download the required version of JDK on the official website. The version I downloaded here is JDK 1.8. After downloading, unzip it:

[root@ java]# tar -zxvf jdk-8u201-linux-x64.tar.gz

1.2 Set environment variables

[root@ java]# vi /etc/profile
添加如下配置：

export JAVA_HOME=/usr/java/jdk1.8.0_201  
export JRE_HOME=${JAVA_HOME}/jre  
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib  
export PATH=${JAVA_HOME}/bin:$PATH
执行 source 命令，使得配置立即生效：

[root@ java]# source /etc/profile

1.3 Check whether the installation is successful

[root@ java]# java -version
显示出对应的版本信息则代表安装成功。

java version "1.8.0_201"
Java(TM) SE Runtime Environment (build 1.8.0_201-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.201-b09, mixed mode)

2. Configure password-free login

Communication between Hadoop components needs to be based on SSH.

2.1 Configuration mapping

Configure ip address and host name mapping:

vim /etc/hosts
# 文件末尾增加
192.168.43.202  hadoop001

2.2 Generate public and private keys

Execute the following command line to generate public and private keys:

ssh-keygen -t rsa

2.3 Authorization

Go to the ~/.ssh directory, view the generated public and private keys, and write the public key to the authorization file:

[root@@hadoop001 sbin]#  cd ~/.ssh
[root@@hadoop001 .ssh]# ll
-rw-------. 1 root root 1675 3 月  15 09:48 id_rsa
-rw-r--r--. 1 root root  388 3 月  15 09:48 id_rsa.pub

# 写入公匙到授权文件
[root@hadoop001 .ssh]# cat id_rsa.pub >> authorized_keys
[root@hadoop001 .ssh]# chmod 600 authorized_keys

3. Hadoop (HDFS) environment construction

3.1 Download and unzip

Download the Hadoop installation package, here I downloaded the CDH version, the download address is: http://archive.cloudera.com/cdh5/cdh/5/

# 解压
tar -zvxf hadoop-2.6.0-cdh5.15.2.tar.gz

3.2 Configure environment variables

# vi /etc/profile
配置环境变量：

export HADOOP_HOME=/usr/app/hadoop-2.6.0-cdh5.15.2
export  PATH=${HADOOP_HOME}/bin:$PATH
执行 source 命令，使得配置的环境变量立即生效：

# source /etc/profile

3.3 Modify Hadoop configuration

Enter the ${HADOOP_HOME}/etc/hadoop/ directory and modify the following configuration:

hadoop-env.sh

# JDK安装路径
export  JAVA_HOME=/usr/java/jdk1.8.0_201/

core-site.xml

<configuration>
<property>
    <!--指定 namenode 的 hdfs 协议文件系统的通信地址-->
    <name>fs.defaultFS</name>
    <value>hdfs://hadoop001:8020</value>
</property>
<property>
    <!--指定 hadoop 存储临时文件的目录-->
    <name>hadoop.tmp.dir</name>
    <value>/home/hadoop/tmp</value>
</property>
</configuration>

hdfs-site.xml

指定副本系数和临时文件存储位置：
<configuration>
<property>
    <!--由于我们这里搭建是单机版本，所以指定 dfs 的副本系数为 1-->
    <name>dfs.replication</name>
    <value>1</value>
</property>
</configuration>

slaves

配置所有从属节点的主机名或 IP 地址，由于是单机版本，所以指定本机即可：
hadoop001

3.4 Turn off the firewall

不关闭防火墙可能导致无法访问 Hadoop 的 Web UI 界面：

# 查看防火墙状态
sudo firewall-cmd --state
# 关闭防火墙:
sudo systemctl stop firewalld.service

3.5 Initialization

第一次启动 Hadoop 时需要进行初始化，进入 ${HADOOP_HOME}/bin/ 目录下，执行以下命令：

[root@hadoop001 bin]# ./hdfs namenode -format

3.6 Start HDFS

进入 ${HADOOP_HOME}/sbin/ 目录下，启动 HDFS：

[root@hadoop001 sbin]# ./start-dfs.sh

3.7 Verify whether the startup is successful

方式一：执行 jps 查看 NameNode 和 DataNode 服务是否已经启动：

[root@hadoop001 hadoop-2.6.0-cdh5.15.2]# jps
9137 DataNode
9026 NameNode
9390 SecondaryNameNode
方式二：查看 Web UI 界面，端口为 50070：

A complete hadoop installation, it is recommended to collect

4. Hadoop (YARN) environment construction

4.1 Modify configuration

Enter the ${HADOOP_HOME}/etc/hadoop/ directory and modify the following configuration:

mapred-site.xml

# 如果没有mapred-site.xml，则拷贝一份样例文件后再修改
cp mapred-site.xml.template mapred-site.xml
<configuration>
<property>
    <name>mapreduce.framework.name</name>
    <value>yarn</value>
</property>
</configuration>

yarn-site.xml

<configuration>
<property>
    <!--配置 NodeManager 上运行的附属服务。需要配置成 mapreduce_shuffle 后才可以在 Yarn 上运行 MapReduce 程序。-->
    <name>yarn.nodemanager.aux-services</name>
    <value>mapreduce_shuffle</value>
</property>
</configuration>

4.2 Start service


进入 ${HADOOP_HOME}/sbin/ 目录下，启动 YARN：

./start-yarn.sh

4.3 验证是否启动成功
```bash
方式一：执行 jps 命令查看 NodeManager 和 ResourceManager 服务是否已经启动：

[root@hadoop001 hadoop-2.6.0-cdh5.15.2]# jps
9137 DataNode
9026 NameNode
12294 NodeManager
12185 ResourceManager
9390 SecondaryNameNode
方式二：查看 Web UI 界面，端口号为 8088：

A complete hadoop installation, it is recommended to collect

For more dry goods, pay attention to: [Data is great]

A complete hadoop installation, it is recommended to collect