本地ip为192.0.4.138，远程访问是报错，如下：
ictester@ic-tester:~$ mysql --host 192.0.4.138 -u root -p12345
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1130 (HY000): Host '192.0.4.133' is not allowed to connect to this MySQL server
需要开启远程权限，
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '12345';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
上述错误是因为设置的密码太简单了，
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_length=4;
Query OK, 0 rows affected (0.00 sec)
然后再执行：
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '12345';
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
此时远端可以正常访问了
mysql --host 192.0.4.138 -u root -p12345
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.7.27 MySQL Community Server (GPL)
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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.
