ubuntu ERROR 1698 (28000): Access denied for user 'root'@'localhost'错误处理

一，问题描述：

ubuntu18.02 新装了mysql-server-5.7,

问题一，普通用户不能进mysql：

~$ mysql -u root -p
Enter password: 
ERROR 1698 (28000): Access denied for user 'root'@'localhost'

  

问题二，su root ，直接用root权限登录就不用密码：

~&su root 
~$ mysql
 Success!

二，解决步骤：

停止mysql服务

~$ sudo service mysql stop
 

以安全模式启动MySQL

~$ sudo mysqld_safe --skip-grant-tables &
 

MySQL启动之后就可以不用密码登陆了

~$ mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.10 MySQL Community Server (GPL)
 

查看一下user表，错误的起因就是在这里， root的plugin被修改成了auth_socket，用密码登陆的plugin应该是mysql_native_password。

mysql> select user, plugin from mysql.user;
+-----------+-----------------------+
| user      | plugin                |
+-----------+-----------------------+
| root      | auth_socket           |
| mysql.sys | mysql_native_password |
| dev       | mysql_native_password |
+-----------+-----------------------+
3 rows in set (0.01 sec)

 

关于auth_socket，在官方有说明： https://dev.mysql.com/doc/mysql-security-excerpt/5.5/en/socket-authentication-plugin.html ，反正现在暂时不用它， 那就把这里改了。

mysql> update mysql.user set authentication_string=PASSWORD('newPwd'), plugin='mysql_native_password' where user='root';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

 

重启服务，问题就解决了

~$ sudo service mysql stop
...
 * MySQL Community Server 5.7.10 is stopped
~$ sudo service mysql start
..
 * MySQL Community Server 5.7.10 is started
~$ mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.10 MySQL Community Server (GPL)