## 安装MySQL
打开MySQL官网的下载页`https://www.mysql.com/downloads/`，点击图示中的Yum Repository菜单
:-: 
往下拉，找到适合MySQL80的下载链接，点进去，不用注册登录，在页面最下端找到“No thanks, just start my download.”，右键复制下载链接。
~~~
https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm
~~~
该页面也提供了MySQL Yum源的使用手册，点击链接进去就可以查看了：
:-: 
导入Yum源：
~~~
[root@localhost ~]# rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm
[root@localhost ~]# yum makecache fast
~~~
Yum源导入成功，可以安装MySQL8.0了
~~~
[root@localhost ~]# yum install mysql-community-server
~~~
显示：
~~~
===========================================================================================================
Package Arch Version Repository Size
===========================================================================================================
Installing:
mysql-community-server x86_64 8.0.12-1.el7 mysql80-community 349 M
Transaction Summary
===========================================================================================================
Install 1 Package
Total download size: 349 M
Installed size: 1.5 G
Is this ok [y/d/N]:
~~~
> 注：为什么默认会安装最新版本，而且没有提供其它版本的MySQL供你选择？因为在`/etc/yum.repos.d/mysql-community.repo`中已经设置其它版本`disabled`了。如果你要安装其它版本的MySQL，只需要设置这个版本的`enabled=1`即可。
确认是MySQL8.0.12无误，输入`y`确认执行安装。
349M，需要一点时间安装。安装完成后，检查版本：
~~~
[root@localhost ~]# mysql -V
~~~
输出：
~~~
mysql Ver 8.0.12 for Linux on x86_64 (MySQL Community Server - GPL)
~~~
版本正确。现在配置MySQL服务：
检查mysqld服务是否启动：
~~~
[root@localhost ~]# systemctl status mysqld.service
~~~
返回：
~~~
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: inactive (dead)
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
~~~
没有启动，我们启动它：
~~~
[root@localhost ~]# systemctl enable mysqld.service
[root@localhost ~]# systemctl start mysqld.service
[root@localhost ~]# systemctl status mysqld.service
~~~
结果：
~~~
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: active (running) since Wed 2018-08-15 12:31:09 CST; 10s ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Process: 1703 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 1773 (mysqld)
Status: "SERVER_OPERATING"
CGroup: /system.slice/mysqld.service
└─1773 /usr/sbin/mysqld
Aug 15 12:31:00 localhost.localdomain systemd[1]: Starting MySQL Server...
Aug 15 12:31:09 localhost.localdomain systemd[1]: Started MySQL Server.
~~~
小绿灯闪耀，天气真好。
安装程序为`root@localhost`创建了初始密码，通过下面的命令查看：
~~~
[root@localhost log]# grep 'temporary password' /var/log/mysqld.log
~~~
输出：
~~~
2018-08-15T06:11:28.416464Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: 8Ftm8eb!S9/(
~~~
这里就是你的初始密码了，需要先修改它：
~~~
[root@localhost log]# mysql -uroot -p
~~~
输入初始密码：
~~~
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';
~~~
~~~
Query OK, 0 rows affected (0.01 sec)
~~~
~~~
mysql> show databases;
~~~
~~~
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.02 sec)
~~~
~~~
mysql> quit';
~~~
关闭虚拟机，拍个快照吧
由于MySQL 8.0 开始改变了身份验证插件，使用以前版本的客户端连接时，可能会报Authentication plugin 'caching\_sha2\_password' cannot be loaded错误，如果出现这种情况，参考下面文章的方案解决：
[http://www.cnblogs.com/hlhx/p/mysqlsha2.html](http://www.cnblogs.com/hlhx/p/mysqlsha2.html)
[https://blog.csdn.net/faye0412/article/details/80396113](https://blog.csdn.net/faye0412/article/details/80396113)
