1. 配置 yum 源
下载并安装 MySQL 源安装包：
> sudo yum localinstall https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
检查 yum 源是否安装成功：
> sudo yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64 MySQL Connectors Community 95
mysql-tools-community/x86_64 MySQL Tools Community 84
mysql57-community/x86_64 MySQL 5.7 Community Server 327
2. yum 安装 MySQL
> sudo yum install mysql-community-server
3. 启动 MySQL
> sudo systemctl enable mysqld
> sudo systemctl start mysqld
> sudo systemctl status mysqld
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: active (running) since Sat 2019-02-16 00:41:07 CST; 2 days ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Main PID: 29143 (mysqld)
Tasks: 31
Memory: 193.2M
CGroup: /system.slice/mysqld.service
└─29143 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
Feb 16 00:41:06 localhost.localdomain systemd[1]: Starting MySQL Server...
Feb 16 00:41:07 localhost.localdomain systemd[1]: Started MySQL Server.
4. 修改 root 初始密码
MySQL 5.7 启动后，会在/var/log/mysqld.log文件中为用户root生成一个随机的初始密码。使用以下命令查看初始密码：
> grep 'temporary password' /var/log/mysqld.log
2019-02-15T16:29:45.738097Z 1 [Note] A temporary password is generated for root@localhost: jHsg<YlYu5id
登录 MySQL 并修改密码：
> mysql -u root -p
Enter password:
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';
MySQL 5.7 默认安装了密码安全检查插件（validate_password），默认密码检查策略要求密码必须包含：大小写字母、数字和特殊符号，并且长度不少于 8 位。
通过 MySQL 环境变量可以查看密码策略的相关信息：
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 |
+--------------------------------------+--------+
7 rows in set (0.01 sec)
指定密码校验策略：
> sudo vi /etc/my.cnf
[mysqld]
# 添加如下键值对, 0=LOW, 1=MEDIUM, 2=STRONG
validate_password_policy=0
禁用密码策略：
> sudo vi /etc/my.cnf
[mysqld]
# 禁用密码校验策略
validate_password = off
重启 MySQL 服务，使配置生效：
sudo systemctl restart mysqld
5. 添加远程登录用户
MySQL 默认只允许root用户在本地登录。如果要从其他机器上连接 MySQL，必须允许root用户从远程登录，或者添加一个允许远程连接的账户。以下命令将添加一个新用户admin，并允许其从远程登录：
mysql> GRANT ALL PRIVILEGES ON *.* TO 'admin'@'%' IDENTIFIED BY 'secret' WITH GRANT OPTION;
如果需要修改权限允许root远程登录，则先以root用户登录 MySQL，再进行如下操作：
mysql> USE mysql;
Database changed
mysql> SELECT User, Host
-> FROM user;
+-----------+---------------+
| Host | User |
+-----------+---------------+
| % | admin |
| localhost | mysql.session |
| localhost | mysql.sys |
| localhost | root |
+-----------+---------------+
4 rows in set (0.02 sec)
mysql> UPDATE user
-> SET Host = '%'
-> WHERE User = 'root';
Query OK, 1 row affected (0.04 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> SELECT User, Host
-> FROM user;
+-----------+---------------+
| Host | User |
+-----------+---------------+
| % | admin |
| % | root |
| localhost | mysql.session |
| localhost | mysql.sys |
+-----------+---------------+
4 rows in set (0.00 sec)
6. 配置默认编码为 UTF-8
MySQL 默认编码为latin1，查看字符集：
mysql> SHOW VARIABLES LIKE 'character%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
在配置文件/etc/my.cnf中将其修改为utf8：
> vim /etc/my.cnf
[mysqld]
# 在myslqd下添加如下键值对
character_set_server=utf8
init_connect='SET NAMES utf8'
重启 MySQL，使配置生效：
> sudo systemctl restart mysqld
再次查看字符集：
mysql> SHOW VARIABLES LIKE 'character%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
7. 开启防火墙端口
> sudo firewall-cmd --zone=public --add-port=3306/tcp --permanent
> sudo firewall-cmd --reload
