Host is not allowed to connect to this MySQL server解决方法

先说说这个错误，其实就是我们的MySQL不允许远程登录，所以远程登录失败了，解决方法如下：

在装有MySQL的机器上登录MySQL mysql -u root -p密码
执行use mysql;
执行update user set host = '%' where user = 'root';这一句执行完可能会报错，不用管它。
执行FLUSH PRIVILEGES;

[root@iZbp143t3oxhfc3ar7jey0Z ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 12
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 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> update user set host = '%' where user = 'root';
ERROR 1062 (23000): Duplicate entry '%-root' for key 'PRIMARY'

mysql> select user, host from user;
+------+-------------------------+
| user | host                    |
+------+-------------------------+
| root | %                       |
| root | 127.0.0.1               |
| root | ::1                     |
| root | izbp143t3oxhfc3ar7jey0z |
+------+-------------------------+
4 rows in set (0.00 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

mysql>

就可以登陆成功了