hadoop note

#JAVA_HOME
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.242.b08-0.el7_7.x86_64/jre
export PATH=$PATH:$JAVA_HOME/bin

#HADOOP_HOME
export HADOOP_HOME=/opt/module/hadoop-2.10.0
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin

https://hadoop.apache.org/docs/r2.10.0/hadoop-project-dist/hadoop-common/SingleCluster.html

 　　

# set to the root of your Java installation
   export JAVA_HOME=/usr/java/latest

$ bin/hadoop

$ mkdir input
$ cp etc/hadoop/*.xml input
$ bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.10.0.jar grep input output 'dfs[a-z.]+'
$ cat output/*
　


$ vim etc/hadoop/core-site.xml
<configuration>
    <property>
        <name>fs.defaultFS</name>
        <value>hdfs://localhost:9000</value>
    </property>

    <property>
         <name>hadoop.tmp.dir</name>
         <value>/opt/module/hadoop-2.10.0/data/tmp</value>
    </property>
</configuration>

$ vim etc/hadoop/hdfs-site.xml
<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
</configuration>

centos yum 安装 java中没有jps命令
需要另外安装devel包，这样就包含jps

yum install java-1.8.0-openjdk-devel.x86_64

$ bin/hdfs namenode -format

$ hadoop-daemon.sh start namenode
$ hadoop-daemon.sh start datanode