mysql>  select host,user from mysql.user;
+-----------+----------+
| host      | user     |
+-----------+----------+
| %         | backup   |
| %         | zjzc_app |
| 127.0.0.1 | root     |
| ::1       | root     |
| localhost | root     |
+-----------+----------+
5 rows in set (0.01 sec)

mysql> quit
Bye
[root@slave ~]# set -o vi
[root@slave ~]# mysql -uzjzc_app -p1234567 
Warning: Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'zjzc_app'@'localhost' (using password: YES)

从数据库无法登陆, 原因为主从同步的时候也同步了mysql数据

replicate-ignore-db = mysql
replicate-ignore-db = information_schema


[root@slave ~]# mysql -uzjzc_app -p1234567 
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 3
Server version: 5.6.22-log Source distribution

Copyright (c) 2000, 2014, 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> quit