Hadoop study notes _2: environment construction (JDK+Hadoop)

Environment setup

• Virtual machine cloning and static IP configuration (you can refer to the blog post listed below as a reference configuration)

  • CentOS 7 minimal installation precautions and installation of some prerequisite components

  • CentOS7 configure static IP-1

  • CentOS7 configure static IP-2

  • How to clone an installed virtual machine VMware clone a virtual machine

  • XShell upload files to Linux server-install lrzsz

• In opt, a new directory module, softwarefolder. Store the decompressed files and compressed file packages separately.
  
  

• JDKInstallation configuration

  ## 解压jdk压缩包
  tar -zxvf jdk-8u144-linux-x64.tar.gz -C /opt/module/
  ## 进入/etc/profile 配置环境变量
  vim /etc/profile
  ## 文件末尾写入配置
  export JAVA_HOME=/opt/module/jdk1.8.0_144
  export PATH=$PATH:$JAVA_HOME/bin
  ## 重新加载Profile文件
  source /etc/profile
  ## 查看jdk安装情况
  $ java -version
  java version "1.8.0_144"
  Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
  Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)
  

• HadoopInstallation configuration

  ## 解压hadoop压缩包
  tar -zxvf hadoop-2.7.2.tar.gz -C /opt/module/
  ## 进入/etc/profile 配置环境变量
  vim /etc/profile
  ## 文件末尾写入配置
  export HADOOP_HOME=/opt/module/hadoop-2.7.2
  export PATH=$PATH:$HADOOP_HOME/bin
  export PATH=$PATH:$HADOOP_HOME/sbin
  ## 重新加载profile文件
  source /etc/profile
  ## 查看Hadoop安装情况
  $ hadoop
  Usage: hadoop [--config confdir] [COMMAND | CLASSNAME]
    CLASSNAME            run the class named CLASSNAME
   or
    where COMMAND is one of:
    fs                   run a generic filesystem user client
    version              print the version
    jar <jar>            run a jar file
                         note: please use "yarn jar" to launch
                               YARN applications, not this command.
    checknative [-a|-h]  check native hadoop and compression libraries availability
    distcp <srcurl> <desturl> copy file or directories recursively
    archive -archiveName NAME -p <parent path> <src>* <dest> create a hadoop archive
    classpath            prints the class path needed to get the
    credential           interact with credential providers
                         Hadoop jar and the required libraries
    daemonlog            get/set the log level for each daemon
    trace                view and modify Hadoop tracing settings
  
  Most commands print help when invoked w/o parameters.
  

  After adding an environment variable in /etc/profile, it can only take effect in the current terminal after compiling with source /etc/profile. After restarting a terminal, the environment variable becomes invalid and can be resolved after restarting the system.

  The /etc/profilescreenshot of the final configuration file is:
  
  important directory:

  [root@localhost hadoop-2.7.2]# ll
  总用量 28
  drwxr-xr-x 2 root root   194 5月  22 2017 bin
  drwxr-xr-x 3 root root    20 5月  22 2017 etc
  drwxr-xr-x 2 root root   106 5月  22 2017 include
  drwxr-xr-x 3 root root    20 5月  22 2017 lib
  drwxr-xr-x 2 root root   239 5月  22 2017 libexec
  -rw-r--r-- 1 root root 15429 5月  22 2017 LICENSE.txt
  -rw-r--r-- 1 root root   101 5月  22 2017 NOTICE.txt
  -rw-r--r-- 1 root root  1366 5月  22 2017 README.txt
  drwxr-xr-x 2 root root  4096 5月  22 2017 sbin
  drwxr-xr-x 4 root root    31 5月  22 2017 share
  

  • bin directory: store scripts for operating Hadoop related services (HDFS, YARN)
  • etc directory: Hadoop configuration file directory, storing Hadoop configuration files
  • lib directory: store Hadoop local library (compress and decompress data)
  • sbin directory: store scripts to start or stop Hadoop related services
  • share directory: store Hadoop dependent jar packages, documents, and official cases