查看預設密碼

[root@localhost src]# cat /var/log/mysqld.log | grep password
2020-12-14T15:54:47.527379Z 6 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: p8ZiC1psfn_r

登入MySQL

mysql -u root -p

更改密碼

ALTER USER 'root'@'localhost' IDENTIFIED BY 'yourpassword';

• MySQL密碼驗證規則和舊版MySQL不同，需調整Validation策略設置才能改成舊版的驗證方式，且需要先設置一組新密碼

調整Mysql Validation策略設置

查看Mysql Validation策略設置

mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password.check_user_name    | ON     |
| 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)

調整設置(暫時性)

mysql> set global validate_password.length=6;
mysql> set global validate_password.policy=LOW;

• 此設置為暫時性的設置，重啟後便會恢復成預設

調整默認validation 策略設置

設置/etc/my.cnf
於[mysqld]下最後加上下列兩行

validate_password.length=6
validate_password.policy=LOW

儲存後重啟Mysql

systemctl restart mysqld

設置可遠端連線進資料庫

use mysql;
update user set host='%' where user='root';

設置完畢後刷新資料庫設置並離開MySQL bash

mysql> FLUSH PRIVILEGES;
mysql> exit

使用更改後的密碼重新登入一次，若能成功登入就是修改密碼成功了

若Mysql客戶端軟體(Navicat等)提示 client does not support authentication protocol requested by server consider upgrading mysql client 錯誤時解決方法

ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY 'yourpassword';
FLUSH PRIVILEGES;

參考資料

MySQL 8 error - ERROR 1819 (HY000): Your password does not satisfy the current policy requirements.
https://stackoverflow.com/questions/50093144/mysql-8-0-client-does-not-support-authentication-protocol-requested-by-server
MySQL 8 error - client does not support authentication protocol requested by server consider upgrading mysql client
https://stackoverflow.com/questions/50093144/mysql-8-0-client-does-not-support-authentication-protocol-requested-by-server