05-001 Mariadb修改root密码及跳过授权方式启动数据库

Mariadb修改root密码

说明：最近在虚拟机上运行的centos7.5中，mariadb的root密码忘记了，后台登录不上去

默认情况下，新安装的 mariadb 的密码为空，在shell终端直接输入 mysql 就能登陆数据库。
如果是刚安装第一次使用，可以使用 mysql_secure_installation 命令初始化密码等配置。

[root@cos7 ~ ]#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, we'll need the current
password for the root user.  If you've just installed MariaDB, and
you haven't 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.

Set 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 anyone
to 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] y
... Success!

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 you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

忘记了 root 密码，则需要以跳过授权的方式启动 mariadb 来修改密码

1、停掉服务。

# systemctl stop mariadb

2、使用跳过授权的方式启动 mariadb。

# mysqld_safe --skip-grant-tables &
[1] 2773
[root@centos7 ~]# 170531 02:10:28 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
170531 02:10:28 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
 
#ps -ef |grep 2770
root       2770   2655  0 16:16 pts/0    00:00:00 /bin/sh /usr/bin/mysqld_safe --skip-grant-tables
mysql      2837   2770  0 16:16 pts/0    00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --skip-grant-tables --log-error=/var/lib/mysql/cos7.localdomain.err --pid-file=cos7.localdomain.pid
root       2877   2655  0 16:17 pts/0    00:00:00 grep --color=auto 2770

3、跳过授权启动，可以不要密码直接登陆数据库。登陆到mysql更新密码。

#mysql
MariaDB [(none)]> use mysql;  
MariaDB [mysql]> UPDATE user SET password=password('newpassword') WHERE user='root';  
MariaDB [mysql]> flush privileges;   
MariaDB [mysql]> exit; 

密码更新后，在跳过授权启动时需要密码登陆。

4、关闭跳过授权启动的进程：

# kill -9 2770

5、正常启动 mariadb：

# systemctl start mariadb

此方法和上述方法雷同

[root@cos7 ~ ]#vim /etc/my.cnf.d/server.cnf
[mysqld]
skip-grant-tables
[root@cos7 ~ ]#systemctl restart mariadb.service
[root@cos7 ~ ]#mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 10.2.19-MariaDB MariaDB Server

Copyright (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)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| my_db              |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.00 sec)

MariaDB [(none)]> 

已知 root 密码，需要修改密码
1、执行如下bash命令

# mysqladmin -uroot -poldpassword password newpassword

2、登陆数据库修改密码。

# mysql -uroot -p
 
2.1 更新 mysql 库中 user 表的字段：
MariaDB [(none)]> use mysql;  
MariaDB [mysql]> UPDATE user SET password=password('newpassword') WHERE user='root';  
MariaDB [mysql]> flush privileges;  
MariaDB [mysql]> exit;
 
2.2 或者使用 set 指令设置root密码：
MariaDB [(none)]> SET password for 'root'@'localhost'=password('newpassword');  
MariaDB [(none)]> exit;

#此条命令不能在跳过授权的情况下执行，否则报错，如下
#MariaDB [mysql]> set password for root@localhost=password('newpassword');
#ERROR 1290 (HY000): The MariaDB server is running with the --skip-grant-#tables option so it cannot execute this statement