报错

Host '172.16.252.129' is not allowed to connect to this MySQL server

意思是无法访问，即没有host权限。

解决方案

将root权限开放为所有主机。

# mysql -u root -p
>mysql SELECT DISTINCT CONCAT('User: ''',user,'''@''',host,''';') AS query FROM mysql.user; 
+---------------------------------------+
| query                                 |
+---------------------------------------+
| User: 'root'@'127.0.0.1';             |
| User: 'root'@'::1';                   |
| User: 'root'@'localhost';             |
| User: 'root'@'localhost.localdomain'; |
+---------------------------------------+
4 rows in set (0.01 sec)

mysql> update mysql.user set host = '%' where host = 'localhost';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql> SELECT DISTINCT CONCAT('User: ''',user,'''@''',host,''';') AS query FROM mysql.user;
+---------------------------------------+
| query                                 |
+---------------------------------------+
| User: 'root'@'%';                     |
| User: 'root'@'127.0.0.1';             |
| User: 'root'@'::1';                   |
| User: 'root'@'localhost.localdomain'; |
+---------------------------------------+
4 rows in set (0.00 sec)

# service mysql restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL. SUCCESS!