CentOS7安装MySQL并允许远程登录

下载 mysql 源安装包

$ curl -LO http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

安装 mysql 源

$ sudo yum localinstall 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           MySQL Connectors Community              21
mysql-tools-community                MySQL Tools Community                   38
mysql57-community                    MySQL 5.7 Community Server             130

如上所示，找到了 mysql 的安装包

2.安装

$ sudo yum install mysql-community-server

3.启动

安装服务

$ sudo systemctl enable mysqld

启动服务

$ sudo systemctl start mysqld

查看服务状态

$ sudo systemctl status mysqld

4.修改 root 默认密码

MySQL 5.7 启动后，在 /var/log/mysqld.log 文件中给 root 生成了一个默认密码。通过下面的方式找到 root 默认密码，然后登录 mysql 进行修改：

$ grep 'temporary password' /var/log/mysqld.log
[Note] A temporary password is generated for root@localhost: **********

登录 MySQL 并修改密码

$ mysql -u root -p
Enter password:
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';

注意：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，并且长度不能少于 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)

具体修改，参见 http://dev.mysql.com/doc/refman/5.7/en/validate-password-options-variables.html#sysvar_validate_password_policy

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 帐户在本地登录，如果要在其它机器上连接 MySQL，必须修改 root 允许远程连接，或者添加一个允许远程连接的帐户，为了安全起见，本例添加一个新的帐户：

mysql> GRANT ALL PRIVILEGES ON *.* TO 'admin'@'%' IDENTIFIED BY 'secret' WITH GRANT OPTION;

mysql> grant all privileges on *.* to 'root'@'%' identified by '123456' with grant option;

mysql> flush privileges; 

6.配置默认编码为 utf8

MySQL 默认为 latin1, 一般修改为 UTF-8

$ vi /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 服务，使配置生效

$ sudo systemctl restart mysqld

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.开启端口

$ sudo firewall-cmd --zone=public --add-port=3306/tcp --permanent
$ sudo firewall-cmd --reload