一、实验环境
CentOS Linux release 7.5.1804 (Core)
mysql Ver 15.1 Distrib 5.5.56-MariaDB, for Linux (x86_64) using readline 5.1
二、实施方案
第一步：添加--skip-grant-tables
在/etc/my.cnf.d/server.cnf中[mysqld]下面添加选项
[mysqld]
skip-grant-tables
第二步：重启数据库
[root@ken ~]# systemctl restart mariadb
第三步：登录数据库
现在发现可以在不输入密码的情况下直接登录进数据库
[root@ken ~]# mysql -uroot
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 2
Server version: 5.5.56-MariaDB MariaDB Server Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]>
第四步：修改密码
这个时候使用grant修改密码会报如下的错误
MariaDB [(none)]> grant all on *.* to root@'localhost' identified by '123'; ERROR 1290 (HY000): The MariaDB server is running with the --skip-grant-tables option so it cannot execute this statement
使用set修改密码也会报同样的错误
MariaDB [(none)]> set password for root@localhost=password('123'); ERROR 1290 (HY000): The MariaDB server is running with the --skip-grant-tables option so it cannot execute this statement
现在使用update即可进行修改
MariaDB [(none)]> use mysql; #切换至mysql数据库
Database changed
MariaDB [mysql]> update user set password=password('123') where user='root'; Query OK, 3 rows affected (0.00 sec) Rows matched: 4 Changed: 3 Warnings: 0
第五步：注销掉配置文件中的选项
[root@ken ~]# vim /etc/my.cnf.d/server.cnf
...
[mysqld]
#skip-grant-tables
第六步：重启数据库
[root@ken ~]# systemctl restart mariadb
第七步：再次登录进行验证
现在不输入密码被直接拒绝
[root@ken ~]# mysql -uroot
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
输入密码123即可进行登录
[root@ken ~]# mysql -uroot -p123
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 3
Server version: 5.5.56-MariaDB MariaDB Server Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]>