linux下MySQL忘记root密码#yyds干货盘点#

Posted 2022-02-24 wangzx_mm

mysql忘记root密码

如果使用 MySQL 数据库忘记了root账号密码，可以通过调节配置文件，跳过密码的方式登数据库，在数据库里面修改账号密码，一般默认的账号是 root

1.问题现象

​​在登录数据库过程中，如果遇到忘记root密码时，该如何解决？​​

2.解决方法

2.1.安装mariadb

通过yum安装mariadb-server，默认依赖安装mariadb，一个是服务端、一个是客户端。

yum -y install mariadb mariadb-server

2.2.配置mariadb

#安装完成后首先要把MariaDB服务开启，并设置为开机启动systemctl start mariadb # 开启服务systemctl enable mariadb # 设置为开机自启动服务#首次安装需要进行数据库的配置，命令都和mysql的一样mysql_secure_installation

[root@localhost ~]# mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, well need the current
password for the root user.  If youve just installed MariaDB, and
you havent set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none):
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

You already have a root password set, so you can safely answer n.

Change the root password? [Y/n] y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables
.. ... Success!

By default, a MariaDB installation has an anonymous user, allowing anyoneto
log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y 
... Success!

Normally, root should only be allowed to connect from localhost.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] n 
... skipping.

By default, MariaDB comes with a database named test that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] y 
- Dropping test database... 
... Success! 
- Removing privileges on test database...
... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y 
... Success!

Cleaning up...

All done!  If youve completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

解释说明：
Enter current password for root (enter for none): # 输入数据库超级管理员root的密码(注意不是系统root的密码)，第一次进入还没有设置密码则直接回车
Set root password? [Y/n] # 设置密码，y
New password: # 新密码Re-enter new password: # 再次输入密码
Remove anonymous users? [Y/n] # 移除匿名用户，y 
Disallow root login remotely? [Y/n] # 拒绝root远程登录，n，不管y/n，都会拒绝root远程登录
Remove test database and access to it? [Y/n] # 删除test数据库，y：删除。n：不删除，数据库中会有一个test数据库，一般不需要
Reload privilege tables now? [Y/n] # 重新加载权限表，y。或者重启服务也行

2.3.测试是否能够登录成功

出现 MariaDB [(none)]> 就表示已经能够正常登录使用MariaDB数据库了

[root@localhost ~]# mysql -uroot -pEnter password:Welcome to the MariaDB monitor.  Commands end with ; or \\g.Your MariaDB connection id is 19Server version: 5.5.68-MariaDB MariaDB ServerCopyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.Type help; or \\h for help. Type \\c to clear the current input statement.MariaDB [(none)]>

3.设置mariadb字符集为utf-8

3.1.修改my.cnf文件

在 [mysqld] 标签下添加init_connect=SET collation_connection = utf8_unicode_ciinit_connect=SET NAMES utf8character-set-server=utf8collation-server=utf8_unicode_ciskip-character-set-client-handshake

3.2.修改my.cnf.d/client.cnf文件

在 [client] 标签下添加default-character-set=utf8

3.3./my.cnf.d/mysql-clients.cnf 文件

在 [mysql] 标签下添加default-character-set=utf8

4.重启服务

systemctl restart mariadb

5.进入mariadb查看字符集

MariaDB [(none)]> show variables like "%character%";show variables like "%collation%";+--------------------------+----------------------------+| Variable_name | Value |+--------------------------+----------------------------+| character_set_client | utf8 || character_set_connection | utf8 || character_set_database | utf8 || character_set_filesystem | binary || character_set_results | utf8 || character_set_server | utf8 || character_set_system | utf8 || character_sets_dir | /usr/share/mysql/charsets/ |+--------------------------+----------------------------+8 rows in set (0.00 sec)+----------------------+-----------------+| Variable_name | Value |+----------------------+-----------------+| collation_connection | utf8_unicode_ci || collation_database | utf8_unicode_ci || collation_server | utf8_unicode_ci |+----------------------+-----------------+3 rows in set (0.00 sec)MariaDB [(none)]>

6.忘记mariadb数据库root密码

经测试，此方法在centos7和centos8上都可成功执行恢复

版本：Server version: 10.3.17-MariaDB MariaDB Servermariadb-5.5.68-1.el7.x86_64mariadb-server-5.5.68-1.el7.x86_64

解释：在mariadb/mysql中，官方保留了一个特权模式

6.1.停止数据库服务

root@localhost ~]# systemctl stop mariadb[root@localhost ~]# ps -ef | grep mariadbroot 26997 370 0 15:14 pts/3 00:00:00 grep --color=auto mariadb[root@localhost ~]# netstat -lnpt | grep mariadb

停止服务后，需要通过ps查看是否保留相关进程，然后使用netstat命令查看端口占用情况，从上面的反馈信息来看，mariadb服务已经被杀的一干二净了，这时候就可以使用特权模式进行密码修改了。

6.2.启动特权模式

[root@localhost ~]# mysqld_safe --skip-grant-tables &[1] 27480[root@localhost ~]# 211228 15:16:13 mysqld_safe Logging to /var/log/mariadb/mariadb.log.211228 15:16:13 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

6.3.出现上面那些后直接输出mysql,然后回车，就会登录到mariadb数据库

[root@localhost ~]# mysqld_safe --skip-grant-tables &[1] 27480[root@localhost ~]# 211228 15:16:13 mysqld_safe Logging to /var/log/mariadb/mariadb.log.211228 15:16:13 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysqlmysql //此处输入后回车，下面内容可能不会显示，但只要进入数据库就是成功Welcome to the MariaDB monitor. Commands end with ; or \\g.Your MariaDB connection id is 1Server version: 5.5.68-MariaDB MariaDB ServerCopyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.Type help; or \\h for help. Type \\c to clear the current input statement.MariaDB [(none)]>

6.4.选择mysql数据库

MariaDB [(none)]> use mysql;Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -A

6.5.更新root密码

MariaDB [mysql]> update user set password=password(mariadb123) where user=root;Query OK, 3 rows affected (0.00 sec)Rows matched: 3 Changed: 3 Warnings: 0密码改为了mariadb123

6.6.刷新权限并退出登录

MariaDB [mysql]> flush privileges;Query OK, 0 rows affected (0.00 sec)MariaDB [mysql]> exit;Bye

6.7.停止特权模式

[root@localhost ~]# pkill mysqld

6.8.启动mariadb服务

[root@localhost ~]# systemctl start mariadb启动成功之后，尝试使用特权模式的登录命令进行登录，然后发现登录失败，说明特权模式已经关闭了[root@localhost ~]# mysqlERROR 1045 (28000): Access denied for user root@localhost (using password: NO)

7.使用新密码登录

[root@localhost ~]# mysql -uroot -pEnter password:Welcome to the MariaDB monitor. Commands end with ; or \\g.Your MariaDB connection id is 5Server version: 5.5.68-MariaDB MariaDB ServerCopyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.Type help; or \\h for help. Type \\c to clear the current input statement.MariaDB [(none)]>