背景：

本地测试环境想跑点东西，就整个三节点的hadoop2.7.7吧。也跑过3.3.0的版本。本地正好跟着友凡老师的教程做些东西，他的课程都是2.6.0的版本。也不想先升级太快不匹配各种找问题了。就找了个2.7.7的包本地跑一跑了

基础环境

主机名	ip	系统
hadoop1	192.168.0.192	centos8.2
hadoop2	192.168.0.192	centos8.2
hadoop3	192.168.0.128	centos8.2

注：关于主机名的修改hostnamectl set-hostname XXX

嗯，别忘了修改三台主机的hosts文件:

开始安装：

1. java环境的配置

我的java环境是提前搭建好的（hadoop1-3节点）：

[root@hadoop1 hadoop]# java -version
java version "1.8.0_291"
Java(TM) SE Runtime Environment (build 1.8.0_291-b10)
Java HotSpot(TM) 64-Bit Server VM (build 25.291-b10, mixed mode

具体安装java环境如下：

https://www.oracle.com/java/technologies/javase/javase-jdk8-downloads.html下载jdk包。我是下载了jdk-8u291-linux-x64.tar.gz

tar zxvf jdk-8u291-linux-x64.tar.gz
mv jdk1.8.0_291  /usr/java/jdk1.8.0_291

vi /etc/profile

export JAVA_HOME=/usr/java/jdk1.8.0_291
export CLASSPATH=$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib
export PATH=/usr/local/mysql/bin:$JAVA_HOME/bin:$PATH

source /etc/profile
###验证版本：
java -verison

2. hadoop环境的安装

1. 下载hadoop安装包

hadoop1节点执行

wget  https://archive.apache.org/dist/hadoop/common/hadoop-2.7.7/hadoop-2.7.7.tar.gz
tar zxvf hadoop-2.7.7.tar.gz
mv hadoop-2.7.7 /usr/local/hadoop

2. 用户配置

不想用root用户默认启动了，跟着大佬们的步骤创建一个hadoop用户吧！

useradd hadoop && echo 'hadoop' | passwd --stdin hadoop && for i in 1 2 3; do ssh root@hadoop${i} "useradd hadoop && echo 'hadoop' | passwd --stdin hadoop && id hadoop"; done

3. 设置hadoop用户秘钥登录集群每个节点

注： hadoop1节点执行

## 切换hadoop用户
su - hadoop
## 生成ssh-keygen
ssh-keygen -t rsa -P ''
## 复制ssh-key秘钥到其他节点
for i in 1 2 3; do ssh-copy-id -i .ssh/id_rsa.pub hadoop@hadoop${i}; done
## 创建所需要目录并修改目录权限
for i in 1 2 3; do ssh root@hadoop${i} "mkdir -pv  /data/hadoop/hdfs/{nn,snn,dn}"; done
for i in 1 2 3; do ssh root@hadoop${i} "chown -R hadoop:hadoop /data/hadoop/hdfs/"; done

4. hadoop 配置文件调整

注：仍然在hadoop1节点修改

vi /usr/local/hadoop/etc/hadoop/hadoop-env.sh

export JAVA_HOME=/usr/java/jdk1.8.0_291

vi /usr/local/hadoop/etc/hadoop/core-site.xml

<configuration>
    <property>
        <name>fs.defaultFS</name>
        <value>hdfs://hadoop1:8020</value>
    </property> 
</configuration>

vi /usr/local/hadoop/etc/hadoop/yarn-site.xml

<configuration>
    <property>
        <name>yarn.resourcemanager.address</name>
        <value>hadoop1:8032</value>
    </property>
    <property>
        <name>yarn.resourcemanager.scheduler.address</name>
        <value>hadoop1:8030</value>
    </property>
    <property>
        <name>yarn.resourcemanager.resource-tracker.address</name>
        <value>hadoop1:8031</value>
    </property>
    <property>
        <name>yarn.resourcemanager.admin.address</name>
        <value>hadoop1:8033</value>
    </property>
    <property>
        <name>yarn.resourcemanager.webapp.address</name>
        <value>hadoop1:8088</value>
    </property>
    <property>
        <name>yarn.nodemanager.aux-services</name>
        <value>mapreduce_shuffle</value>
    </property>
    <property>
        <name>yarn.nodemanager.auxservices.mapreduce_shuffle.class</name>
        <value>org.apache.hadoop.mapred.ShuffleHandler</value>
    </property>
    <property>
        <name>yarn.resourcemanager.scheduler.class</name>
        <value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler</value>
    </property>
</configuration>

vim /usr/local/hadoop/etc/hadoop/hdfs-site.xml

<configuration>
    <property>
        <name>dfs.replication</name>
        <value>2</value>
    </property>
    <property>
        <name>dfs.namenode.name.dir</name>
        <value>file:///data/hadoop/hdfs/nn</value>
    </property>
    <property>
        <name>dfs.datanode.data.dir</name>
        <value>file:///data/hadoop/hdfs/dn</value>
    </property>
    <property>
        <name>fs.checkpoint.dir</name>
        <value>file:///data/hadoop/hdfs/snn</value>
    </property>
    <property>
        <name>fs.checkpoint.edits.dir</name>
        <value>file:///data/hadoop/hdfs/snn</value>
    </property>
</configuration>

vim /usr/local/hadoop/etc/hadoop/mapred-site.xml

<configuration>
    <property>
        <name>mapreduce.framework.name</name>
        <value>yarn</value>
    </property>
</configuration>

vi /usr/local/hadoop/etc/hadoop/slaves

hadoop2
hadoop3

5. 将hadoop文件同步到其他节点（hadoop2 hadoop3)

for i in 2 3; do scp -r /usr/local/hadoop  hadoop${i}:/usr/local/hadoop/; done

注意：记录检查一下目录文件的权限 /usr/local/hadoop目录下文件权限都chown -R hadoop:hadoop *下。还有/data/hadoop目录下权限！

6. 将hadoop系统变量添加到profile

vi /etc/profile

export HADOOP_HOME=/usr/local/hadoop
export HADOOP_PREFIX=/usr/local/hadoop
export PATH=$PATH:${HADOOP_PREFIX}/bin:${HADOOP_PREFIX}/sbin
export HADOOP_YARN_HOME=${HADOOP_PREFIX}
export HADOOP_MAPPERD_HOME=${HADOOP_PREFIX}
export HADOOP_COMMON_HOME=${HADOOP_PREFIX}
export HADOOP_HDFS_HOME=${HADOOP_PREFIX}

source /etc/profile

7. hadoop初始化-格式化hdfs

su - hadoop
hdfs namenode -format 

8. 启动dfs yarn 服务

start-dfs.sh

嗯报错了目录权限的问题。

cd /usr/local/hadoop
chown hadoop.hadoop -R logs

重新启动yarn与dfs。当然了也有可能还没有创建logs目录。手动创建一下啊可以。关键注意的还是目录的权限

9. web访问hadoop对应服务

嗯可以绑定host 的方式访问hadoop1:50070

也可以直接http://192.168.0.192:50070/

访问yarn

关于日志的查看就直接去/user/local/hadoop/logs目录下查看就可以了！

2021-06-04-Centos8 安装hadoop 2.7.7（3节点）

背景：