MySQL 5.7忘記root密碼后修改的詳細(xì)教程

更新時(shí)間：2017年05月07日 15:02:39 作者：瀟湘隱者

因?yàn)殚L(zhǎng)時(shí)間不操作mysql而忘記root密碼的朋友估計(jì)不在少數(shù)，最近發(fā)現(xiàn)在MySQL 5.7版本下用之前的方法修改密碼不能成功了，所以只能重新想辦法解決，下面這篇文章主要給大家介紹了MySQL 5.7忘記root密碼后修改的詳細(xì)教程，需要的朋友可以參考。

前言

一直以來(lái)，MySQL的應(yīng)用和學(xué)習(xí)環(huán)境都是MySQL 5.6和之前的版本，也沒(méi)有去關(guān)注新版本MySQL 5.7的變化和新特性。今天幫人處理忘記root密碼的時(shí)時(shí)候，發(fā)現(xiàn)以前的方法不奏效了。

具體情況如下所示：

案例環(huán)境如下：

操作系統(tǒng) ： Red Hat Enterprise Linux Server release 6.6 (Santiago)

數(shù)據(jù)庫(kù)版本： 5.7.18 MySQL Community Server (GPL)

忘記密碼，輸入錯(cuò)誤的密碼時(shí)遇到下面錯(cuò)誤信息：

[root@mytestlnx02 ~]# mysql -u root -p
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
[root@mytestlnx02 ~]#

檢查MySQL服務(wù)是否啟動(dòng)，如果啟動(dòng)，關(guān)閉MySQL服務(wù)

[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

然后啟動(dòng)MySQL，進(jìn)入MySQL后，修改root密碼,操作過(guò)程中遇到ERROR 1054 (42S22): Unknown column 'password' in 'field list'，查了一下user表的表結(jié)構(gòu)，發(fā)現(xiàn)原來(lái)MySQL 5.7下，user表已經(jīng)沒(méi)有Password字段。加密后的用戶密碼存儲(chǔ)于authentication_string字段。

具體操作過(guò)程如下所示：

[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，把剛才加入的那一行“skip-grant-tables”注釋或刪除掉。然后重啟MySQL服務(wù)后需要執(zhí)行命令set password=password('newpassword');后，問(wèn)題搞定。

[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)

后面查詢了一下相關(guān)資料，發(fā)現(xiàn)MySQL 5.7在安全方面有下一些新特性。

1. 用戶表 mysql.user 的 plugin字段不允許為空，默認(rèn)值是 mysql_native_password，而不是 mysql_old_password，不再支持舊密碼格式；

2. 增加密碼過(guò)期機(jī)制，過(guò)期后需要修改密碼，否則可能會(huì)被禁用，或者進(jìn)入沙箱模式；是否啟用密碼過(guò)期由參數(shù)default_password_lifetime控制。

mysql> show variables like 'default_password_lifetime';
+---------------------------+-------+
| Variable_name    | Value |
+---------------------------+-------+
| default_password_lifetime | 0  |
+---------------------------+-------+
1 row in set (0.00 sec)
 
mysql>

3：增加了密碼安全等級(jí)以及密碼復(fù)雜度設(shè)置。參數(shù)如下：

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 初始化時(shí)，默認(rèn)會(huì)自動(dòng)生成隨機(jī)密碼,隨機(jī)密碼放在/var/log/mysqld.log中，并且不創(chuàng)建除 root@localhost和mysql.sys@localhost 外的其他賬號(hào)，也不創(chuàng)建 test 庫(kù)；

[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)

總結(jié)

以上就是這篇文章的全部?jī)?nèi)容了，希望本文的內(nèi)容對(duì)大家的學(xué)習(xí)或者工作能帶來(lái)一定的幫助，如果有疑問(wèn)大家可以留言交流，謝謝大家對(duì)腳本之家的支持。

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