《MySQL 5.7忘记root密码如何修改?Mysql应用》要点:
本文介绍了MySQL 5.7忘记root密码如何修改?Mysql应用,希望对您有用。如果有疑问,可以联系我们。
			           
- [root@mytestlnx02 ~]# mysql -u root -p
 - Enter password:
 - ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
 - [root@mytestlnx02 ~]#
 
检查MySQL服务是否启动,如果启动,关闭MySQL服务
 MYSQL数据库
- [root@mytestlnx02 ~]# ps -ef | grep -i mysql
 - root 22972 1 0 14:18 pts/0 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --pid-file=/var/run/mysqld/mysqld.pid --basedir=/usr --user=mysql
 - mysql 23166 22972 0 14:18 pts/0 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/lib/mysql/mysql.sock
 - root 23237 21825 0 14:22 pts/0 00:00:00 grep -i mysql
 - [root@mytestlnx02 ~]# service mysqld stop
 - Stopping mysqld: [ OK ]
 - [root@mytestlnx02 ~]#
 
找到MySQL的my.cnf配置文件,在/etc/my.cnf (有些版本是/etc/mysql/my.cnf)在里面增加下面一段信息:
[mysqld]
skip-grant-tables
然后启动MySQL,进入MySQL后,修改root密码,操作过程中遇到ERROR 1054 (42S22): Unknown column 'password' in 'field list',查了一下user表的表结构,发现原来MySQL 5.7下,user表已经没有Password字段.加密后的用户密码存储于authentication_string字段.具体操作过程如下所示:
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- [root@mytestlnx02 ~]# service mysqld start
 - Starting mysqld: [ OK ]
 - [root@mytestlnx02 ~]# mysql -u root
 - Welcome to the MySQL monitor. Commands end with ; or \g.
 - Your MySQL connection id is 4
 - Server version: 5.7.18 MySQL Community Server (GPL)
 - Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
 - Oracle is a registered trademark of Oracle Corporation and/or its
 - affiliates. Other names may be trademarks of their respective
 - owners.
 - Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 - mysql> use mysql;
 - Reading table information for completion of table and column names
 - You can turn off this feature to get a quicker startup with -A
 - Database changed
 - mysql> update user set password=PASSWORD('Kd8k&dfdl023')
 - -> where user='root';
 - ERROR 1054 (42S22): Unknown column 'password' in 'field list'
 - mysql> update mysql.user set authentication_string=password('Kd8k&dfdl023') 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)
 - mysql> exit
 

在my.cnf文件中,把刚才加入的那一行“skip-grant-tables”注释或删除掉. 然后重启MySQL服务后需要执行命令set password=password('newpassword');后,问题搞定.
 MYSQL数据库
- [root@mytestlnx02 ~]# service mysqld start
 - Starting mysqld: [ OK ]
 - [root@mytestlnx02 ~]# mysql -u root -p
 - Enter password:
 - Welcome to the MySQL monitor. Commands end with ; or \g.
 - Your MySQL connection id is 4
 - Server version: 5.7.18
 - Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
 - Oracle is a registered trademark of Oracle Corporation and/or its
 - affiliates. Other names may be trademarks of their respective
 - owners.
 - Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 - mysql> use mysql;
 - ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
 - mysql> set password=password('Kd8k&dfdl023');
 - Query OK, 0 rows affected, 1 warning (0.00 sec)
 
后面查询了一下相关资料,发现MySQL 5.7在安全方面有下一些新特性(参考MySQL 5.7版本新特性连载(三))
1. 用户表 mysql.user 的 plugin字段不允许为空, 默认值是 mysql_native_password,而不是 mysql_old_password,不再支持旧密码格式;
2. 增加密码过期机制,过期后需要修改密码,否则可能会被禁用,或者进入沙箱模式; 是否启用密码过期由参数default_password_lifetime控制.
 MYSQL数据库
- mysql> show variables like 'default_password_lifetime';
 - +---------------------------+-------+
 - | Variable_name | Value |
 - +---------------------------+-------+
 - | default_password_lifetime | 0 |
 - +---------------------------+-------+
 - 1 row in set (0.00 sec)
 - mysql>
 
3:增加了密码安全等级以及密码复杂度设置.参数如下:
 MYSQL数据库
- mysql> show variables like 'validate_password%';
 - +--------------------------------------+--------+
 - | Variable_name | Value |
 - +--------------------------------------+--------+
 - | validate_password_check_user_name | OFF |
 - | 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 (0.00 sec)
 
4. 使用 mysql_install_db 初始化时,默认会自动生成随机密码,随机密码放在/var/log/mysqld.log中,并且不创建除 root@localhost和mysql.sys@localhost 外的其他账号,也不创建 test 库;
 MYSQL数据库
- [root@mytestlnx02 mysql]# yum localinstall mysql-community-{server,client,common,libs}-*
 - [root@mytestlnx02 mysql]# rpm -qa | grep -i mysql
 - mysql-community-client-5.7.18-1.el6.i686
 - mysql-community-libs-5.7.18-1.el6.i686
 - perl-DBD-MySQL-4.013-3.el6.x86_64
 - mysql-community-server-5.7.18-1.el6.i686
 - mysql-community-common-5.7.18-1.el6.i686
 - mysql-community-libs-compat-5.7.18-1.el6.i686
 - [root@mytestlnx02 mysql]# service mysqld start
 - Initializing MySQL database: [ OK ]
 - Installing validate password plugin: [ OK ]
 - Starting mysqld: [ OK ]
 - [root@mytestlnx02 mysql]#
 - [root@mytestlnx02 mysql]# grep 'temporary password' /var/log/mysqld.log
 - 2017-05-05T06:10:57.802143Z 1 [Note] A temporary password is generated for root@localhost: w99s(m-q_ML:
 - mysql> select user ,host from user;
 - +-----------+-----------+
 - | user | host |
 - +-----------+-----------+
 - | mysql.sys | localhost |
 - | root | localhost |
 - +-----------+-----------+
 - 2 rows in set (0.00 sec)
 
MYSQL数据库
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