MySQL修改root密码的方法常见问题及解决方法
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mysql修改root密码的方法
作为守护数据库安全的第一道关卡是root账户及其密码。
学会对root密码管理无疑是守门人和开锁人的一项基础技能。
知道密码的情况
在已知密码的情况下,可以登录MySQL数据库后,通过ALTER USER(MySQL 5.7.6以上版本)或者SET PASSWORD命令进行修改。
1.使用ALTER USER命令修改密码
在MySQL 5.7.6或则MariaDB 10.1.20以上的版本可以使用ALTER USER命令修改用户密码
例:
--登录mysql
-bash-4.1$ mysql -u root -p
mysql> alter user root identified by 'MyNewPass4!';
Query OK, 0 rows affected (0.02 sec)
2.使用SET PASSWORD命令修改密码
使用SET PASSWORD命令修改Mysql的用户密码。
MySQL 5.7以后版本:
例:
SET PASSWORD FOR <用户名>@<host名> = 'my_new_password';
--当前用户
mysql> SET PASSWORD = 'my_new_password';
Query OK, 0 rows affected (0.33 sec)
MySQL 5.7以前版本需要PASSWORD()函数。
例:
mysql> SET PASSWORD = PASSWORD('new_password');
参考:
https://dev.mysql.com/doc/refman/8.0/en/alter-user.html
13.7.1.1 ALTER USER Statement
https://dev.mysql.com/doc/refman/8.0/en/set-password.html
13.7.1.10 SET PASSWORD Statement
忘记密码的情况
在不知道root密码(密码丢失)的情况下,可以通过如下方法登录mysql修改密码。
使用–init-file
可以通过创建一个包含密码语句本地文件,然后使用–init-file选项启动MySQL。
例:
创建一个本地文件
-bash-4.1$ vi /refresh/home/init-file.txt
文件内容如下:
ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass2!';
确认文件内容:
-bash-4.1$ cat /refresh/home/init-file.txt
ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass2!';
- 关闭MySQL
-bash-4.1$ sudo service mysqld status
mysqld (pid 2031) is running...
-bash-4.1$ sudo service mysqld stop
Stopping mysqld: [ OK ]
-bash-4.1$ sudo service mysqld status
mysqld is stopped
Linux 7以后可以使用如下systemctl命令。
systemctl stop mysqld.service
或者
/etc/init.d/mysqld stop
- 使用如下命令启动MySQL
-bash-4.1$ sudo mysqld --user=mysql --init-file=/refresh/home/init-file.txt &
[1] 2255
-
通过新密码进行连接测试。
mysql -u root -p
使用–skip-grant-tables
可以使用使用–skip-grant-tables选项启动Mysql ,从而跳过权限验证登录MySQL后修改root密码。
- 关闭MySQL
-bash-4.1$ sudo service mysqld status
mysqld (pid 2031) is running...
-bash-4.1$ sudo service mysqld stop
Stopping mysqld: [ OK ]
-bash-4.1$ sudo service mysqld status
mysqld is stopped
Linux 7以后可以使用如下systemctl命令。
systemctl stop mysqld.service
或者
/etc/init.d/mysqld stop
- 使用–skip-grant-tables启动MySQL
-bash-4.1$ sudo mysqld --skip-grant-tables --user=mysql &
[1] 29840
-bash-4.1$ mysql
Welcome to the MySQL monitor. Commands end with ; or \\g.
Your MySQL connection id is 7
Server version: 8.0.23 MySQL Community Server - GPL
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
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>
- 重新加载授权表,以便帐户管理语句起作用。
mysql> flush privileges;
Query OK, 0 rows affected (0.05 sec)
- 修改root密码
mysql> ALTER USER root identified by 'MyNewPass1!';
Query OK, 0 rows affected (0.02 sec)
- 测试用新密码登录MySQL
-bash-4.1$ mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \\g.
Your MySQL connection id is 9
Server version: 8.0.23 MySQL Community Server - GPL
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
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>
- 正常重启MySQL
-bash-4.1$ sudo service mysqld status
mysqld (pid 29841) is running...
-bash-4.1$ sudo service mysqld stop
Stopping mysqld: [ OK ]
[1]+ Done sudo mysqld --skip-grant-tables --user=mysql
-bash-4.1$ sudo service mysqld status
mysqld is stopped
-bash-4.1$ sudo service mysqld start
Starting mysqld: [ OK ]
或者
-bash-4.1$ sudo service mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
测试连接:
-bash-4.1$ mysql -u root -p
参考:
https://dev.mysql.com/doc/refman/8.0/en/server-options.html
5.1.7 Server Command Options
https://dev.mysql.com/doc/refman/8.0/en/resetting-permissions.html
B.3.3.2 How to Reset the Root Password
B.3.3.2.2 Resetting the Root Password: Unix and Unix-Like Systems
B.3.3.2.3 Resetting the Root Password: Generic Instructions
常见问题及解决
mysql> set password for root@localhost = password(‘123’);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘password(‘123’)’ at line 1
密码没有加上引号
mysql> alter user root@localhost identified by pass;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘pass’ at line 1
ERROR 1819 (HY000)
修改密码时发生ERROR 1819 (HY000) 错误
mysql> alter user root@localhost identified by 'pass';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
原因:密码不满足安全要求
MySQL数据库的高版本(5.7以后)默认会有validate_password插件,该插件启用后将强制实施密码验证策略。如果新密码不满足密码验证策略就会报ERROR 1819 (HY000) 错误。
级别 | 长度 | 字符类型 | 单词匹配 |
---|---|---|---|
LOW | 至少为8个字符 | N/A | N/A |
MEDIUM | 同上 | 必须包含至少1个数字字符,1个小写字符,1个大写字符和1个特殊(非字母数字)字符 | N/A |
STRONG | 同上 | 同上 | 必须与字典文件中的单词不匹配 |
参数(5.7) | validate_password_length | validate_password_number_count validate_password_mixed_case_count validate_password_special_char_count | validate_password_dictionary_file |
参数(8.0) | validate_password.length | validate_password.number_count validate_password.mixed_case_count validate_password.special_char_count | validate_password.dictionary_file |
默认密码策略是MEDIUM。
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------+--------+
| validate_password.check_user_name | ON |
| 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 (0.14 sec)
解决方法:
降低策略的级别
--5.7
mysql> SET GLOBAL validate_password_policy=LOW;
OR
mysql> SET GLOBAL validate_password_policy=0;
--8.0
mysql> set global validate_password.policy=LOW;
OR
mysql> set global validate_password.policy=0;
例:
mysql> set global validate_password.policy=LOW;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| validate_password.check_user_name | ON |
| validate_password.dictionary_file | |
| validate_password.length | 8 |
| validate_password.mixed_case_count | 1 |
| validate_password.number_count | 1 |
| validate_password.policy | LOW |
| validate_password.special_char_count | 1 |
+--------------------------------------+-------+
7 rows in set (0.00 sec)
单独修改策略项
例:
mysql> alter user root identified by 'pass';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql> SET GLOBAL validate_password.length = 4;
Query OK, 0 rows affected (0.00 sec)
mysql> alter user root identified by 'pass';
Query OK, 0 rows affected (0.05 sec)
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| validate_password.check_user_name | ON |
| validate_password.dictionary_file | |
| validate_password.length | 4 | ★★
| validate_password.mixed_case_count | 1 |
| validate_password.number_count | 1 |
| validate_password.policy | LOW |
| validate_password.special_char_count | 1 |
+--------------------------------------+-------+
7 rows in set (0.00 sec)
参考:
https://dev.mysql.com/doc/refman/8.0/en/validate-password.html
6.4.3 The Password Validation Component
ERROR 1396 (HY000)
mysql> alter user root@localhost identified by 'my_new_pass';
ERROR 1396 (HY000): Operation ALTER USER failed for 'root'@'localhost'
原因:
用户的host不一致。
mysql> alter user root@localhost identified by 'my_new_pass';
ERROR 1396 (HY000): Operation ALTER USER failed for 'root'@'localhost'
mysql> show databases
-> ;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
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> select user,host from user;
+------------------+-----------+
| user | host |
+------------------+-----------+
| root | % |
| mysql.infoschema | localhost |
| mysql.session | localhost |
| mysql.sys | localhost |
+------------------+-----------+
4 rows in set (0.00 sec)
解决方法:
修改host名或者去掉host名。
例:
mysql> alter user root@'%' identified by 'my_new_pass';
Query OK, 0 rows affected (0.02 sec)
或者
mysql> alter user root identified by 'my_new_pass';
Query OK, 0 rows affected (0.04 sec)
ERROR 1064 (42000)
mysql> SET PASSWORD = PASSWORD('new_password');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'PASSWORD('new_password')' at line 1
原因:MySQL 5.7 以后不需要PASSWORD()函数。
例:
mysql> SET PASSWORD = 'my_new_password';
Query OK, 0 rows affected (0.02 sec)
使用–skip-grant-tables --user=mysql选项启动出错:Permission denied
使用–skip-grant-tables --user=mysql选项启动出错:Permission denied
-bash-4.1$ mysqld --skip-grant-tables --user=mysql &
[1] 29806
-bash-4.1$ 2021-02-26T00:10:32.691961Z 0 [Warning] [MY-010091] [Server] Can't create test file /var/lib/mysql/mysqld_tmp_file_case_insensitive_test.lower-test
2021-02-26T00:10:32.692079Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.23) starting as process 29806
2021-02-26T00:10:32.698349Z 0 [Warning] [MY-010091] [Server] Can't create test file /var/lib/mysql/mysqld_tmp_file_case_insensitive_test.lower-test
2021-02-26T00:10:32.698375Z 0 [Warning] [MY-010159] [Server] Setting lower_case_table_names=2 because file system for /var/lib/mysql/ is case insensitive
2021-02-26T00:10:32.698711Z 0 [Warning] [MY-010122] [Server] One can only use the --user switch if running as root
2021-02-26T00:10:32.699063Z 0 [ERROR] [MY-010187] [Server] Could not open file '/var/log/mysqld.log' for error logging: Permission denied
2021-02-26T00:10:32.699141Z 0 [ERROR] [MY-010119] [Server] Aborting
2021-02-26T00:10:32.699366Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.23) MySQL Community Server - GPL.
[1]+ Exit 1 mysqld --skip-grant-tables --user=mysql
-bash-4.1$
-bash-4.1$
-bash-4.1$ mysql
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
解决方法:使用sudo 或者root用户
例:
-bash-4.1$ sudo mysqld --skip-grant-tables --user=mysql &
[1] 29840
-bash-4.1$ mysql
Welcome to the MySQL monitor. Commands end with ; or \\g.
Your MySQL connection id is 7
Server version: 8.0.23 MySQL Community Server - GPL
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
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>
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