1.停止mysql 服务

systemctl stop mysqld.service

2.修改/etc/my.cnf ，增加 skip-grant-tables

[mysqld]
skip-grant-tables

3.启动mysql

systemctl start mysqld.service
mysql -u root -p

4.修改密码

use mysql
ALTER USER 'root'@'localhost' IDENTIFIED   BY '123'

5.去掉skip-grant-tables配置，重启mysql

6.修改远程配置

update user set host = '%' where user = 'root';
ALTER USER 'root'@'%' IDENTIFIED BY '123456' PASSWORD EXPIRE NEVER;