CentOS7 yum方法安装MySQL5.7并开启root用户远程连接

1 下载并安装mysql

1.1 下载并安装MySQL官方的 Yum Repository

[[e-mail] ~]# wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm

1.2 下载并安装MySQL的rpm

[[e-mail] ~]# yum -y install mysql57-community-release-el7-10.noarch.rpm

1.3 安装MySQL服务器

[[e-mail] ~]# yum -y install mysql-community-server

出现下面的提示，说明安装成功：

2 MySQL数据库设置

2.1 启动mysql

[[e-mail] src]# systemctl start mysqld  
[[e-mail] src]# systemctl status mysqld

2.2 设置开机启动mysql

[[e-mail] src]# systemctl enable mysqld
[[e-mail] src]# systemctl daemon-reload

2.3 获得mysql初始密码

[[e-mail] src]# grep 'temporary password' /var/log/mysqld.log
2020-04-17T10:59:54.668094Z 1 [Note] A temporary password is generated for [e-mail]: e;omvyN53CS*

2.4 登录mysql

[[e-mail] src]# mysql -uroot -p

用刚才获得的初始密码登录成功后，不能做任何事情，因为MySQL默认必须修改密码之后才能操作数据库，而5.7版本的mysql采用了密码机制，默认为medium，要求密码有大写字母及特殊字符。MySQL完整的初始密码规则可以通过如下命令查看：

mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password_check_user_name    | OFF    |
| validate_password_dictionary_file    |        |
| validate_password_length             | 8      |
| validate_password_mixed_case_count   | 1      |
| validate_password_number_count       | 1      |
| validate_password_policy             | MEDIUM |
| validate_password_special_char_count | 1      |
+--------------------------------------+--------+

2.5 修改mysql的root密码

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'Mypass123!';

到此数据库的密码设置就完成了。
但此时还有一个问题，就是因为安装了Yum Repository，以后每次yum操作都会自动更新，需要把这个卸载掉：

[[e-mail] ~]# yum -y remove mysql57-community-release-el7-10.noarch

3 开启root用户远程连接

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select `user`,authentication_string,`Host` from `user`;
+---------------+-------------------------------------------+-----------+
| user          | authentication_string                     | Host      |
+---------------+-------------------------------------------+-----------+
| root          | *ED6727A34C50DA0C532932E364204F55B6557EAC | localhost |
| mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | localhost |
| mysql.sys     | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | localhost |
+---------------+-------------------------------------------+-----------+

可以看到root目前只支持localhost本机连接。
再执行如下语句：

mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'Mypass123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> select `user`,authentication_string,`Host` from `user`;
+---------------+-------------------------------------------+-----------+
| user          | authentication_string                     | Host      |
+---------------+-------------------------------------------+-----------+
| root          | *ED6727A34C50DA0C532932E364204F55B6557EAC | localhost |
| mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | localhost |
| mysql.sys     | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | localhost |
| root          | *ED6727A34C50DA0C532932E364204F55B6557EAC | %         |
+---------------+-------------------------------------------+-----------+

我们看到root目前已支持任意机器连接，最后还要查看防火墙等问题。