安裝完mysql，爲各個服務增加對應的數據庫和用戶後，發現
無法使用新增的用戶登陸mysql。
但使用用戶登陸失敗：
root@controller:~# mysql -h localhost -ukeystone -ppassword
ERROR 1045 (28000): Access denied for user 'keystone'@'localhost' (using password: YES)
解決方法：
刪除數據庫空用戶
[root@bogon ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
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> SELECT user,host,password FROM mysql.user;
+------+-----------+-------------------------------------------+
| user | host | password |
+------+-----------+-------------------------------------------+
| root | localhost | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| root | bogon | |
| root | 127.0.0.1 | |
| root | ::1 | |
| | localhost | |
| | bogon | |
+------+-----------+-------------------------------------------+
6 rows in set (0.00 sec)
mysql> delete from mysql.user where user='';
Query OK, 2 rows affected (0.02 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> exit
意思是刪除匿名用戶。