MySQL usage notes 1

MySQL and postgresql It is currently the two popular open source databases , Most domestic databases are derived from this ,MySQL From the whole architecture 、 It is similar in design and grammar to the early Sybase,SQLServer Also derived from Sybase, In terms of application SQLServer More friendly , More features , The performance of a single database is also the best ;MySQL There are also many limitations , But here are just experiments and notes , Do not go into .

1、 First landing MySQL, You need to get the initial password from the log

[[email protected] local]# grep 'temporary password' /var/log/mysqld.log
2022-06-16T04:41:36.398736Z 6 [Note] [MY-010454] [Server] A temporary password is generated for [email protected]: oyazXUIps8)F
[[email protected] local]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 8.0.29

Copyright (c) 2000, 2022, 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.

2、 The initial password needs to be updated before each operation , Then modify the password policy that meets the needs

mysql> SHOW VARIABLES LIKE 'validate_password.%';
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '[email protected]';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '1qaz!QAZ';
Query OK, 0 rows affected (0.01 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             | MEDIUM |
| validate_password.special_char_count | 1      |
+--------------------------------------+--------+
7 rows in set (0.02 sec)

mysql> set global validate_password.length=6;
Query OK, 0 rows affected (0.00 sec)

mysql> set global validate_password.policy=0;
Query OK, 0 rows affected (0.00 sec)

mysql> set global validate_password.check_user_name=off;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW VARIABLES LIKE 'validate_password.%';
+--------------------------------------+-------+
| Variable_name                        | Value |
+--------------------------------------+-------+
| validate_password.check_user_name    | OFF   |
| validate_password.dictionary_file    |       |
| validate_password.length             | 6     |
| 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 (0.01 sec)

3、 Enter the data , Modify the user table , Ensure that external users can access MySQL

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 host,user from user where user='root';
+-----------+------+
| host      | user |
+-----------+------+
| localhost | root |
+-----------+------+
1 row in set (0.00 sec)

mysql> update user set host='%' where user='root';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select host,user from user where user='root';
+------+------+
| host | user |
+------+------+
| %    | root |
+------+------+
1 row in set (0.00 sec)

4、 to root User external user empowerment

mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
ERROR 1410 (42000): You are not allowed to create a user with GRANT
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
Query OK, 0 rows affected (0.01 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.01 sec)

mysql> 

5、 Modify the configuration file , binding IP Address , Modify firewall again , Ensure that external users can access the port

[[email protected] local]# netstat -anpt 
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      3667/sshd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      5353/master         
tcp        0     52 192.168.13.50:22        123.123.123.2:52521     ESTABLISHED 4618/sshd: [email protected] 
tcp        0      0 192.168.13.50:22        192.168.13.11:63249     ESTABLISHED 4546/sshd: [email protected] 
tcp        0      0 192.168.13.50:22        123.123.123.2:64545     ESTABLISHED 4569/sshd: [email protected] 
tcp6       0      0 :::3306                 :::*                    LISTEN      5439/mysqld         
tcp6       0      0 :::22                   :::*                    LISTEN      3667/sshd           
tcp6       0      0 ::1:25                  :::*                    LISTEN      5353/master         
tcp6       0      0 :::33060                :::*                    LISTEN      5439/mysqld         
pid-file=/var/run/mysqld/mysqld.pid
[[email protected] local]# vi /etc/my.cnf  
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/8.0/en/server-configuration-defaults.html

[mysqld]

datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

bind-address=0.0.0.0
"/etc/my.cnf" 33L, 1265C written
[[email protected] local]# firewall-cmd --zone=public --add-port=3306/tcp --permanent
success
[[email protected] local]# firewall-cmd --reload 
success
[[email protected] local]# 

Last , Thank you for your attention , Thank you for your support ！