centos7 yum方式安装MySQL5.7

[root@localhost ~]# wget https://repo.mysql.com//mysql57-community-release-el7-10.noarch.rpm
[root@localhost ~]# yum -y install mysql57-community-release-el7-10.noarch.rpm

为避免出现源 "MySQL 5.7 Community Server" 的 GPG 密钥已安装，但是不适用于此软件包。请检查源的公钥 URL 是否配置正确的错误，应导入2022的密钥，见下行命令

[root@localhost ~]# rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022
[root@localhost ~]# yum -y install mysql-community-server
[root@localhost ~]# systemctl start  mysqld.service
[root@localhost ~]# grep "password" /var/log/mysqld.log
2022-08-25T12:57:24.541900Z 1 [Note] A temporary password is generated for root@localhost: uHtloOduj0<I     ##此处为MySQL初始密码uHtloOduj0<I

[root@localhost ~]# mysql -uroot -p
Enter password:     ##此处输入uHtloOduj0<I登录MySQL

修改密码规则

修改为简单密码规则配置，必须修改两个全局参数
1.修改validate_password_policy参数的值的值
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)
2.配置判断密码的标准就基于密码的长度
validate_password_length参数默认为8，他有最小值的限制，最小值为4
mysql> set global validate_password_length=6;
Query OK, 0 rows affected (0.00 sec)

查看MySQL密码配置规则

mysql> show variables like 'validate_password%';
+--------------------------------------+-------+
| Variable_name                        | Value |
+--------------------------------------+-------+
| validate_password_check_user_name    | OFF   |
| validate_password_dictionary_file    |       |
| validate_password_length             | 4     |
| validate_password_mixed_case_count   | 1     |
| validate_password_number_count       | 1     |
| validate_password_policy             | LOW   |
| validate_password_special_char_count | 1     |
+--------------------------------------+-------+
7 rows in set (0.00 sec)

参数解释
validate_password_dictionary_file       ##插件用于验证密码强度的字典文件路径
validate_password_length            ##密码最小长度，参数默认为8，最小值的限制为4
validate_password_mixed_case_count      ##密码至少要包含的小写字母个数和大写字母个数
validate_password_number_count      ##密码至少要包含的数字个数
validate_password_policy        ##密码强度检查登记，0/LOW、1/MEDIUM、2/STRONG，默认是1
validate_password_special_char_count        ##密码至少要包含的特殊字符数

mysql修改密码

mysql> set password for 'root'@'localhost'=password('123123');
Query OK, 0 rows affected, 1 warning (0.00 sec)