Debian下安装hadoop
目标:
配置安装openjdk环境，下载安装hadoop
安装OpenJDK
#先切换到root用户，更新debian的包索引，debian9在系统安装时已选择163的源
su
apt-get update
#然后安装包管理工具aptitude,通过aptitude搜索安装openjdk
apt-get install aptitude
然后尝试搜索openjdk获得安装包名
#aptitude search openjdk
MSDB:/home/ms# aptitude search openjdk
p openjdk-8-dbg - Java runtime based on OpenJDK (debugging s
i openjdk-8-dbg:i386 - Java runtime based on OpenJDK (debugging s
p openjdk-8-demo - Java runtime based on OpenJDK (demos and e
p openjdk-8-demo:i386 - Java runtime based on OpenJDK (demos and e
p openjdk-8-doc - OpenJDK Development Kit (JDK) documentatio
i openjdk-8-jdk - OpenJDK Development Kit (JDK)
p openjdk-8-jdk:i386 - OpenJDK Development Kit (JDK)
i A openjdk-8-jdk-headless - OpenJDK Development Kit (JDK) (headless)
p openjdk-8-jdk-headless:i386 - OpenJDK Development Kit (JDK) (headless)
i A openjdk-8-jre - OpenJDK Java runtime, using Hotspot JIT
i A openjdk-8-jre:i386 - OpenJDK Java runtime, using Hotspot JIT
p openjdk-8-jre-dcevm - Alternative VM for OpenJDK 8 with enhanced
p openjdk-8-jre-dcevm:i386 - Alternative VM for OpenJDK 8 with enhanced
i A openjdk-8-jre-headless - OpenJDK Java runtime, using Hotspot JIT (h
i A openjdk-8-jre-headless:i386 - OpenJDK Java runtime, using Hotspot JIT (h
p openjdk-8-jre-zero - Alternative JVM for OpenJDK, using Zero/Sh
p openjdk-8-jre-zero:i386 - Alternative JVM for OpenJDK, using Zero/Sh
p openjdk-8-source - OpenJDK Development Kit (JDK) source files
因为已经安装了，前面的 i A代表软件包的标记状态，如果没有安装，和上述的有差异，别在意，现在需要安装openjdk-8的jdk和jre(安装软件需要root权限，下面默认登录的用户是root),i386是32位的安装包，目前系统是amd64
aptitude install openjdk-8-jdk
aptitude install openjdk-8-jre
配置运行环境
1.查看openjdk安装目录
openjdk安装目录为/usr/lib/jvm/xxxx（版本共存）
#cd /usr/lib/jvm
#ls -l
总用量 12
lrwxrwxrwx 1 root root 24 1月 6 2017 default-java -> java-1.8.0-openjdk-amd64
drwxr-xr-x 4 root root 4096 10月 19 23:48 java-1.5.0-gcj-6-amd64
lrwxrwxrwx 1 root root 20 7月 23 20:12 java-1.8.0-openjdk-amd64 -> java-8-openjdk-amd64
lrwxrwxrwx 1 root root 19 11月 1 22:17 java-1.8.0-openjdk-i386 -> java-8-openjdk-i386
drwxr-xr-x 7 root root 4096 11月 9 21:16 java-8-openjdk-amd64
drwxr-xr-x 5 root root 4096 11月 9 02:07 java-8-openjdk-i386
default-java是当前系统默认的java，如果没有这个软连接，就手动创建软连接
#ln -s java-1.8.0-openjdk-amd64 default-java
2.配置default-java到环境变量，作为JAVA_HOME,debian9默认shell为bash，编辑~/.bashrc
添加以下内容
export JAVA_HOME=/usr/lib/jvm/default-java
export CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/jre/lib/rt.jar
export PATH=$JAVA_HOME/bin:$PATH
JAVA_HOME用default-java软连接代替实际目录，方便后续java环境升级更改
PATH中设置JAVA_HOME/bin在前保证java命令搜索路径优先
设置完毕后，输入bash回车使得环境变量生效（新shell载入bashrc,后续的bash都生效，已打开的终端）
3.验证环境变量设置
##查看java路径
#which java
/usr/lib/jvm/default-java/bin/java
#which javac
/usr/lib/jvm/default-java/bin/javac
java环境设置完毕
安装Hadoop框架
Hadoop官网:http://hadoop.apache.org
Hadoop官网参考中文文档:http://hadoop.apache.org/docs/r1.0.4/cn/
1.获得Hadoop
通过官网找到稳定发行版,打开页面，找到Download,下载Hadoop2.8.2的binary文件，然后通过浏览器下载，这里使用wget下载
#cd ~
#wget http://mirror.bit.edu.cn/apache/hadoop/common/hadoop-2.8.2/hadoop-2.8.2.tar.gz
正在解析主机 mirror.bit.edu.cn (mirror.bit.edu.cn)... 114.247.56.117
正在连接 mirror.bit.edu.cn (mirror.bit.edu.cn)|114.247.56.117|:80... 已连接。
已发出 HTTP 请求，正在等待回应... 200 OK
长度：243900138 (233M) [application/octet-stream]
正在保存至: “hadoop-2.8.2.tar.gz”
....
下载文件位于/root/hadoop-2.8.2.tar.gz(本次实验为了方便，直接使用root目录)
解压文件到当前目录
tar -xzvf hadoop-2.8.2.tar.gz
....
解压后目录位于/root/hadoop-2.8.2(以下以$HADOOP_HOME描述此目录)
#cd hadoop-2.8.2
#ls
bin etc include lib libexec LICENSE.txt logs NOTICE.txt README.txt sbin share
其中bin下存着hadoop文件
sbin则是hadoop的启动脚本
2.配置Hadoop
由于实验过程中发现了，JAVA_HOME无法被识别，直接配置hadoop-env的JAVA_HOME为实际路径default-java,配置文件位于$HADOOP_HOME/etc/hadoop/hadoop-env.sh(Linux下)
#vim etc/hadoop/hadoop-env.sh
找到文件中JAVA_HOME，修改如下
# The java implementation to use.
export JAVA_HOME=/usr/lib/jvm/default-java
修改完毕后:wq保存
3.JAVA_HOME配置绝对路径后,hadoop不再提示找不到java_home
# bin/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
Hadoop jar and the required libraries
credential interact with credential providers
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.
4.Hadoop的java环境变量以及基本安装完毕
