基于安全考虑root账户一般只能本地访问，但是在开发过程中可能需要打开root的远程访问权限

主机192.168.122.11上登录mysql为root用户打开远程连接权限（针对192.168.122.0/24网段主机）
mysql> grant all privileges on *.* to root@'192.168.122.%' identified by "123456";
Query OK, 0 rows affected (0.02 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.02 sec)

在其他主机上远程连接测试
[root@mysql ~]# mysql -h192.168.122.11 -uroot -p123456
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.5.25a-log Source distribution

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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.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| baidu              |
| mysql              |
| newdb              |
| performance_schema |
| song               |
| test               |
+--------------------+
7 rows in set (0.01 sec)