部署條件準備
需要3臺虛擬機master(192.138.137.161)，slaver01(192.138.137.162)，slaver02(192.138.137.163)
系統centos8，配置1核CPU，2G內存，20G硬盤
軟件包：hadoop-3.2.2.tar.gz，jdk-8u191-linux-x64.tar.gz
安裝虛擬機和設置靜態ip聯網可以參考如下：
安裝虛擬機Centos8：https://blog.csdn.net/dp340823/article/details/112056146
宿主機連接wifi，centos8靜態IP聯網：https://blog.csdn.net/dp340823/article/details/112056911
一、安裝jdk和hadoop
這些操作是在master(192.138.137.161)進行的，
後續將文件scp到slaver01(192.138.137.162)和slaver02(192.138.137.163)即可
1.上傳軟件包到指定目錄下
2.將jdk解壓到指定目錄/opt下
tar zxvf jdk-8u191-linux-x64.tar.gz -C /opt
3.將hadoop解壓到指定目錄/opt下
tar zxvf hadoop-3.2.1.tar.gz -C /opt
4.修改環境變量並使之生效
vim /etc/profile
#java
export JAVA_HOME=/opt/jdk1.8.0_191
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
#hadoop
export HADOOP_HOME=/opt/hadoop-3.2.1
export PATH=$PATH:$HADOOP_HOME/bin
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
source /etc/profile
5.驗證jdk和hadoop安裝是否正確
java -version
hadoop version
二、設置ssh免密登錄
3臺虛擬機都要做
1.關閉防火牆
systemctl stop firewalld
firewall-cmd --state
2.修改 hosts
vim /etc/hosts
192.168.137.161 master
192.168.137.162 slaver01
192.168.137.163 slaver02
3.生成公鑰
ssh-keygen -t rsa一直回車即可
4.公鑰複製到其他機器上
ssh-copy-id master
ssh-copy-id slaver01
ssh-copy-id slaver02
5.驗證登錄
ssh master
三、修改hadoop配置文件
配置文件都在/opt/hadoop-3.2.1/etc/hadoop/目錄下
1.修改配置文件hadoop-env.sh（在末尾添加已下內容）
vim /opt/hadoop-3.2.1/etc/hadoop/hadoop-env.sh
export JAVA_HOME=/opt/jdk1.8.0_191
export HDFS_NAMENODE_USER=root
export HDFS_DATANODE_USER=root
export HDFS_SECONDARYNAMENODE_USER=root
2.修改配置文件core-site.xml
vim /opt/hadoop-3.2.1/etc/hadoop/core-site.xml
<!-- 指定HDFS老大（namenode）的通信地址 -->
<property>
<name>fs.defaultFS</name>
<value>hdfs://master:9000</value>
</property>
<!-- 指定hadoop運行時產生文件的存儲路徑 -->
<property>
<name>hadoop.tmp.dir</name>
<value>/opt/hadoop-3.2.1/tmp</value>
</property>
3.修改配置文件hdfs-site.xml
vim /opt/hadoop-3.2.1/etc/hadoop/hdfs-site.xml
<!-- 設置namenode的http通訊地址 -->
<property>
<name>dfs.namenode.http-address</name>
<value>master:50070</value>
</property>
<!-- 設置secondarynamenode的http通訊地址 -->
<property>
<name>dfs.namenode.secondary.http-address</name>
<value>slaver01:50090</value>
</property>
<!-- 設置namenode存放的路徑 -->
<property>
<name>dfs.namenode.name.dir</name>
<value>/opt/hadoop-3.2.1/name</value>
</property>
<!-- 設置hdfs副本數量 -->
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
<!-- 設置datanode存放的路徑 -->
<property>
<name>dfs.datanode.data.dir</name>
<value>/opt/hadoop-3.2.1/data</value>
</property>
4.修改配置文件mapred-site.xml
vim /opt/hadoop-3.2.1/etc/hadoop/mapred-site.xml
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
5.修改配置文件yarn-site.xml
vim /opt/hadoop-3.2.1/etc/hadoop/yarn-site.xml
<!-- 設置 resourcemanager 在哪個節點-->
<property>
<name>yarn.resourcemanager.hostname</name>
<value>master</value>
</property>
<!-- reducer取數據的方式是mapreduce_shuffle -->
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property> <name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
6.新建masters文件(/opt/hadoop-3.2.1/etc/hadoop/目錄下)
vim masters
7.新建workers文件(/opt/hadoop-3.2.1/etc/hadoop/目錄下)
vim workers
8.新建tmp、name、data文件夾(/opt/hadoop-3.2.1目錄下)
mkdir tmp name data
9.將master機上的複製文件到slaver01、slaver02
scp /etc/profile slaver01:/etc/
scp /etc/profile slaver02:/etc/
scp -r /opt slaver01:/
scp -r /opt slaver02:/需要在slaver01、slaver02執行source /etc/profile 使用配置文件生效
java -version和hadoop version驗證slaver01和slaver02 上的jdk和hadoop是否安裝成功
四、啓動hadoop
3臺虛擬機都要做
1.第一次啓動需要格式化namenode(/opt/hadoop-3.2.1)
./bin/hdfs namenode -format
2.啓動dfs
./sbin/start-dfs.sh
3.啓動yarn
./sbin/start-yarn.sh 
4.用jps驗證
master
slaver01
slaver02
五、訪問應用
1.瀏覽器輸入192.168.137.161:50070
2.瀏覽器輸入192.168.137.161:8088
點擊nodes查看
