hadoop3的单机启动配置

#下载hadoop的tar包
wget https://mirrors.tuna.tsinghua.edu.cn/apache/hadoop/common/hadoop-3.2.1/hadoop-3.2.1.tar.gz
#解压到指定目录
tar -xzvf hadoop-3.2.1.tar.gz /export/server

#修改配置文件 etc/hadoop/core-site.xml

    <property>
        <name>fs.defaultFS</name>
        <value>hdfs://localhost:9000</value>
    </property>

#修改配置文件 hdfs-site
<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
</configuration>

#需要提前安装jdk etc/hadoop/hadoop-env.sh
 export JAVA_HOME= /export/server/jdk1.8.0_171

#配置免密登陆
   ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa
   cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
   chmod 0600 ~/.ssh/authorized_keys
#测试 成功免密配置成功
ssh localhost   

#第一次启动前需要格式化节点 在hadoop目录下
bin/hdfs namenode -format
#启动
sbin/start-dfs.sh

#配置 etc/hadoop/mapred-site.xml
<configuration>
    <property>
        <name>mapreduce.framework.name</name>
        <value>yarn</value>
    </property>
    <property>
        <name>mapreduce.application.classpath</name>
        <value>$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/*:$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/lib/*</value>
    </property>
</configuration>

#配置 etc/hadoop/yarn-site.xml:
<configuration>
    <property>
        <name>yarn.nodemanager.aux-services</name>
        <value>mapreduce_shuffle</value>
    </property>
    <property>
        <name>yarn.nodemanager.env-whitelist</name>
        <value>JAVA_HOME,HADOOP_COMMON_HOME,HADOOP_HDFS_HOME,HADOOP_CONF_DIR,CLASSPATH_PREPEND_DISTCACHE,HADOOP_YARN_HOME,HADOOP_MAPRED_HOME</value>
    </property>
</configuration>

配置 /etc/profile

#检查hadoop是否安装好
echo $HADOOP_HOME
#进入Hadoop安装目录进行格式化
hadoop namenode -format
#启动yarn
sbin/start-yarn.sh
sbin/start-dfs.sh

附加

#centos 安装 ssh
yum install openssh
yum install openssh-server

centos的java安装博客
https://blog.csdn.net/qq_43662627/article/details/109468275

#root用户启动失败 修改 etc/hadoop/hadoop-env.sh 添加如下
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