防止使用过于简单的密码，mysql提供了validate_password密码插件来强制规范密码复杂度。用了这个插件再去创建123456这种密码时操作会报错。
https://dev.mysql.com/doc/refman/5.7/en/validate-password-installation.html
在线安装：
INSTALL PLUGIN validate_password SONAME 'validate_password.so';
或者增加配置然后重启
[mysqld]
plugin-load-add=validate_password.so
show plugins;查看下刚刚安装的validate_password插件
(root@localhost) [(none)]>show plugins;
+----------------------------+----------+--------------------+----------------------+---------+
| Name | Status | Type | Library | License |
+----------------------------+----------+--------------------+----------------------+---------+
| binlog | ACTIVE | STORAGE ENGINE | NULL | GPL |
| mysql_native_password | ACTIVE | AUTHENTICATION | NULL | GPL |
| sha256_password | ACTIVE | AUTHENTICATION | NULL | GPL |
| CSV | ACTIVE | STORAGE ENGINE | NULL | GPL |
| MEMORY | ACTIVE | STORAGE ENGINE | NULL | GPL |
| InnoDB | ACTIVE | STORAGE ENGINE | NULL | GPL |
| INNODB_TRX | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_LOCKS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_LOCK_WAITS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMPMEM | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMPMEM_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_PER_INDEX | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_PER_INDEX_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_PAGE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_PAGE_LRU | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_POOL_STATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_TEMP_TABLE_INFO | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_METRICS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_DEFAULT_STOPWORD | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_DELETED | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_BEING_DELETED | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_CONFIG | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_INDEX_CACHE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_INDEX_TABLE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLESTATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_INDEXES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_COLUMNS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FIELDS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FOREIGN | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FOREIGN_COLS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLESPACES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_DATAFILES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_VIRTUAL | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| MyISAM | ACTIVE | STORAGE ENGINE | NULL | GPL |
| MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL | GPL |
| PERFORMANCE_SCHEMA | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ARCHIVE | ACTIVE | STORAGE ENGINE | NULL | GPL |
| BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL |
| FEDERATED | DISABLED | STORAGE ENGINE | NULL | GPL |
| partition | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ngram | ACTIVE | FTPARSER | NULL | GPL |
| validate_password | ACTIVE | VALIDATE PASSWORD | validate_password.so | GPL |
+----------------------------+----------+--------------------+----------------------+---------+
45 rows in set (0.00 sec)
查看参数 show variables like 'validate%';
(root@localhost) [(none)]>show variables like 'validate%';
+--------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------+--------+
| validate_password_check_user_name | OFF |
| validate_password_dictionary_file | |
| validate_password_length | 8 |
| validate_password_mixed_case_count | 1 |
| validate_password_number_count | 1 |
| validate_password_policy | MEDIUM |
| validate_password_special_char_count | 1 |
+--------------------------------------+--------+
7 rows in set (0.01 sec)
1、validate_password_length 8 密码长度为8位
2、validate_password_mixed_case_count 1 包含一个大写字母
3、validate_password_number_count 1 包含一个数字
4、validate_password_special_char_count 包含一个特殊字符
完了之后修改密码为123，报错如下。密码不安全，不符合validate_password插件的约束。
(root@localhost) [(none)]>alter user david@'%' identified by '123';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
那么我们设置一个符合规范的密码，设置成功
(root@localhost) [(none)]>alter user david@'%' identified by '1111aaA_';
Query OK, 0 rows affected (0.00 sec)
validate_password_dictionary_file 密码字典表
启用这个密码字典表可以做到限制密码不能包含字典中指定的字符串。
创建一个包含admin字符串的文件：
echo 'admin'> dic.file
指定validate_password_dictionary_file和validate_password_policy 值
(root@localhost) [(none)]>set global validate_password_dictionary_file = '/mdata/mysql57/dic.file';
Query OK, 0 rows affected (0.00 sec)
(root@localhost) [(none)]>set global validate_password_policy = STRONG;
Query OK, 0 rows affected (0.00 sec)
现在设置密码为1111adminDD_提示修改失败。去掉admin使用kk代替就成功了。
(root@localhost) [(none)]>alter user david@'%' identified by '1111adminDD_';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
(root@localhost) [(none)]>alter user david@'%' identified by '1111kkDD_';
Query OK, 0 rows affected (0.00 sec)
validate_password_check_user_name
设置ON，约束密码不能直接设置为用户名
set global validate_password_check_user_name= ON;
(root@localhost) [(none)]>alter user david@'%' identified by 'root';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
