centOS_7安装hadoop2.10.0和JAVA1.8.231
相关软件下载地址：
hadoop2.10.0：http://mirror.bit.edu.cn/apache/hadoop/common/
JAVA1.8.231：https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
一、 Hadoop 安装
# 1. 创建hadoop用户
以root用户登陆，创建新用户hadoop，并设置密码。
[root@localhost GMI]# useradd -m hadoop -s /bin/bash
[root@localhost GMI]# passwd hadoop
更改用户 hadoop 的密码 。
新的 密码：
无效的密码： 密码少于 8 个字符
重新输入新的 密码：
passwd：所有的身份验证令牌已经成功更新。
为hadoop用户增加管理员权限：
[root@localhost GMI]# visudo
找到root ALL=(ALL) ALL对应位置，在下一行添加hadoop All=(All) All（注意空格为tab）
## Allow root to run any commands anywhere
root ALL=(ALL) ALL
hadoop All=(All) All
## Allows members of the 'sys' group to run networking, software,
# 2. 安装和配置SSH无密码登陆
新建窗口，以hadoop用户登陆，执行以下命令检查centOS是否安装SSH client、SSH serve
[hadoop@localhost GMI]$ rpm -qaa | grep ssh
openssh-clients-7.4p1-11.el7.x86_64
openssh-7.4p1-11.el7.x86_64
libssh2-1.4.3-10.el7_2.1.x86_64
openssh-server-7.4p1-11.el7.x86_64
若没有安装，执行以下命令：
sudo yum install openssh-clients
sudo yum install openssh-server
测试SSH是否可用：
[hadoop@localhost GMI]$ ssh localhost
The authenticity of host 'localhost (::1)' can't be established.
ECDSA key fingerprint is SHA256:YwEbUdpgN+F8KJjptNpFTJTxevmgMAlRSmGeRQoFwW0.
ECDSA key fingerprint is MD5:4c:30:6d:45:49:44:bf:76:c7:3c:7a:1b:69:ff:fc:99.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts.
hadoop@localhost's password:
Last login: Wed Dec 18 18:10:47 2019
配置SSH无密码登陆
退出SSH
[hadoop@localhost ~]$ exit
登出
Connection to localhost closed.
进入.ssh目录，利用ssh-keygen生成密钥：（遇到提示，全部按回车键）
[hadoop@localhost GMI]$ cd /home/hadoop/.ssh/
[hadoop@localhost .ssh]$ ls
known_hosts
[hadoop@localhost .ssh]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/hadoop/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/hadoop/.ssh/id_rsa.
Your public key has been saved in /home/hadoop/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:Gzr4SCOHolwvDknXqTPriXQ27IHOfjRJyOZRNEnYUXw hadoop@localhost.localdomain
The key's randomart image is:
+---[RSA 2048]----+
| ===. |
| . +.. E |
|. o . |
| = .. . |
|o.o..o S |
|..==.. . o |
|.=+@* o . |
|*.B*O+ . |
|o*+*o.. |
+----[SHA256]-----+
最后，将密钥加入到授权中去，并修改文件权限：
[hadoop@localhost .ssh]$ cat id_rsa.pub >> authorized_keys
[hadoop@localhost .ssh]$ chmod 600 ./authorized_keys
再次登陆ssh命令和ssh localhost命令，则可以无需密码直接登陆：
[root@localhost ~]# ssh
usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]
[-D [bind_address:]port] [-E log_file] [-e escape_char]
[-F configfile] [-I pkcs11] [-i identity_file]
[-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]
[-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]
[-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]
[user@]hostname [command]
[root@localhost ~]# ssh localhost
Last login: Wed Dec 18 18:53:39 2019 from ::1
将压缩包hadoop-2.10.0.tar.gz 拷贝至/home/hadoop
解压文件：
[root@localhost hadoop]# tar -zxvf hadoop-2.10.0.tar.gz
修改文件权限：
[root@localhost hadoop]# chown -R hadoop:hadoop hadoop-2.10.0
验证Hadoop是否安装成功：
[root@localhost hadoop]# ./hadoop-2.10.0/bin/hadoop version
Hadoop 2.10.0
Subversion ssh://git.corp.linkedin.com:29418/hadoop/hadoop.git -r e2f1f118e465e787d8567dfa6e2f3b72a0eb9194
Compiled by jhung on 2019-10-22T19:10Z
Compiled with protoc 2.5.0
From source with checksum 7b2d8877c5ce8c9a2cca5c7e81aa4026
This command was run using /home/hadoop/hadoop-2.10.0/share/hadoop/common/hadoop-common-2.10.0.jar
二、JAVA 安装
root权下新建目录：
[root@localhost hadoop]# mkdir /home/hadoop/java
将JAVA安装包放置该目录下（/home/hadoop/java）：
[root@localhost java]# cd /home/hadoop/java/
[root@localhost java]# ls
jdk-8u231-linux-x64.rpm jdk-8u231-linux-x64.tar.gz
[root@localhost java]# tar -zxvf jdk-8u231-linux-x64.tar.gz
[root@localhost java]# cd ./jdk1.8.0_231/
采用全局设置方法，设置jdk环境，修改~/.bashrc
命令：
内容如下：
# .bashrc
# User specific aliases and functions
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
~
修改后，内容如下
# .bashrc
# User specific aliases and functions
JAVA_HOME=/home/hadoop/java/jdk1.8.0_231
JRE_HOME=/home/hadoop/java/jdk1.8.0_231/jre
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$JAVA_HOME/bin:$PATH
export PATH JAVA_HOME CLASSPATH
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
~
最后，source一下：
[root@localhost java]# source ~/.bashrc
验证JAVA是否安装成功：
[root@localhost java]# java -version
java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)
[root@localhost java]#