由于5.7 的策略已经改变。因此要做点事方可登录。
Step 1:
先退出mysql
Step 2:
mysqld_safe --skip-grant-tables &
你会看到以下信息：
2017-04-17T09:27:25.447837Z mysqld_safe Logging to '/var/log/mysql/mysqld.log'.
2017-04-17T09:27:25.467994Z mysqld_safe Starting mysqld daemon with databases from /data/mysql
Step 3:
ps -ef | grep mysql
root 131849 112122 0 17:27 pts/0 00:00:00 /bin/sh /usr/bin/mysqld_safe --skip-grant-tables
mysql 132011 131849 1 17:27 pts/0 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/data/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --skip-grant-tables --log-error=/var/log/mysql/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/data/mysql/mysql.sock
root 132045 112122 0 17:27 pts/0 00:00:00 grep mysql
Step 4:
执行：
mysql
mysql> use mysql;
mysql> desc user;
mysql> select user,host,authentication_string,password_expired from user;
更改密码的指令：
mysql> update user set authentication_string=password('xxxxxx') where user='root';
Query OK, 1 row affected, 1 warning (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 1mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)mysql> exit
Bye
Step 5:
/etc/rc.d/init.d/mysqld restart
2017-04-17T09:40:42.707647Z mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
停止 mysqld： [确定]
正在启动 mysqld： [确定]
[1]+ Done mysqld_safe --skip-grant-tables
证实一下：
mysql -p
Enter password: <----- 刚才输入的密码
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 5
Server version: 5.7.18-logCopyright (c) 2000, 2017, 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>
来来，设定好了进来爽一下，
mysql> show databases;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
mysql>额，必须重置？必须通过alter user重置一下密码。好吧，乖乖的再重置一下。
mysql> alter user root@'localhost' identified by 'your_are_pig';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements额，看样子密码太过简单，系统让你复杂一点。好吧，复杂一点吧。
mysql> alter user 'root'@'localhost' identified by 'What!!The!!Hell##';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements额，还是太简单？好吧，大小写，加英文字，加符号，加数字试试。。。。
mysql> alter user 'root'@'localhost' identified by 'What!!995##';
Query OK, 0 rows affected (0.01 sec)终于。。。。改。。。成。。。。。功。。。。。。。。再来玩一下。。。
mysql> show database;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'database' at line 1额。。。。唉，少了个s。再来。。。。
mysql> show databases;
不容易啊。。。终于改好可以用了。
基本上就搞定了。
如果，你不想那么复杂的密码，想把该策略关了，那么继续看下去。。。
mysql> SHOW VARIABLES LIKE 'validate_password%';
validate_password_dictionary_file : 插件用于验证密码强度的字典文件路径。
validate_password_length : 密码最小长度。
validate_password_mixed_case_count : 密码至少要包含的小写字母个数和大写字母个数。
validate_password_number_count : 密码至少要包含的数字个数。
validate_password_policy : 密码强度检查等级，0/LOW、1/MEDIUM、2/STRONG。
validate_password_special_char_count: 密码至少要包含的特殊字符数。其中关于validate_password_policy-密码强度检查等级：0.LOW > 只检查长度。1.MEDIUM > 检查长度、数字、大小写、特殊字符。2.STRONG > 检查长度、数字、大小写、特殊字符字典文件。估计有插件在检查策略。
mysql> show plugins;
好吧，估计就是这个了，试试改 ACTIVE 为 DISABLE
简单一点，不下指令了，直接改 my.cnf 文件：
[mysqld]
validate_password=off
然后重启一下mysql，再执行
mysql> show plugins; 。。。截掉前一大半内容。。。 | FEDERATED | DISABLED | STORAGE ENGINE | NULL | GPL | | BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL | | partition | ACTIVE | STORAGE ENGINE | NULL | GPL | | ARCHIVE | ACTIVE | STORAGE ENGINE | NULL | GPL | | ngram | ACTIVE | FTPARSER | NULL | GPL | | validate_password | DISABLED | VALIDATE PASSWORD | validate_password.so | GPL | +----------------------------+----------+--------------------+----------------------+---------+ 45 rows in set (0.01 sec)这时，可以看到 validate_password 已经为disable 状态了。
接下来，顺便也建个用户帐号和密码吧。
建新用户：
先列出用户的表结构看看和之前有没有区别。
mysql> desc mysql.user; +------------------------+-----------------------------------+------+-----+-----------------------+-------+ | Field | Type | Null | Key | Default | Extra | +------------------------+-----------------------------------+------+-----+-----------------------+-------+ | Host | char(60) | NO | PRI | | | | User | char(32) | NO | PRI | | | | Select_priv | enum('N','Y') | NO | | N | | | Insert_priv | enum('N','Y') | NO | | N | | | Update_priv | enum('N','Y') | NO | | N | | | Delete_priv | enum('N','Y') | NO | | N | | | Create_priv | enum('N','Y') | NO | | N | | | Drop_priv | enum('N','Y') | NO | | N | | | Reload_priv | enum('N','Y') | NO | | N | | | Shutdown_priv | enum('N','Y') | NO | | N | | | Process_priv | enum('N','Y') | NO | | N | | | File_priv | enum('N','Y') | NO | | N | | | Grant_priv | enum('N','Y') | NO | | N | | | References_priv | enum('N','Y') | NO | | N | | | Index_priv | enum('N','Y') | NO | | N | | | Alter_priv | enum('N','Y') | NO | | N | | | Show_db_priv | enum('N','Y') | NO | | N | | | Super_priv | enum('N','Y') | NO | | N | | | Create_tmp_table_priv | enum('N','Y') | NO | | N | | | Lock_tables_priv | enum('N','Y') | NO | | N | | | Execute_priv | enum('N','Y') | NO | | N | | | Repl_slave_priv | enum('N','Y') | NO | | N | | | Repl_client_priv | enum('N','Y') | NO | | N | | | Create_view_priv | enum('N','Y') | NO | | N | | | Show_view_priv | enum('N','Y') | NO | | N | | | Create_routine_priv | enum('N','Y') | NO | | N | | | Alter_routine_priv | enum('N','Y') | NO | | N | | | Create_user_priv | enum('N','Y') | NO | | N | | | Event_priv | enum('N','Y') | NO | | N | | | Trigger_priv | enum('N','Y') | NO | | N | | | Create_tablespace_priv | enum('N','Y') | NO | | N | | | ssl_type | enum('','ANY','X509','SPECIFIED') | NO | | | | | ssl_cipher | blob | NO | | NULL | | | x509_issuer | blob | NO | | NULL | | | x509_subject | blob | NO | | NULL | | | max_questions | int(11) unsigned | NO | | 0 | | | max_updates | int(11) unsigned | NO | | 0 | | | max_connections | int(11) unsigned | NO | | 0 | | | max_user_connections | int(11) unsigned | NO | | 0 | | | plugin | char(64) | NO | | mysql_native_password | | | authentication_string | text | YES | | NULL | | | password_expired | enum('N','Y') | NO | | N | | | password_last_changed | timestamp | YES | | NULL | | | password_lifetime | smallint(5) unsigned | YES | | NULL | | | account_locked | enum('N','Y') | NO | | N | | +------------------------+-----------------------------------+------+-----+-----------------------+-------+ 45 rows in set (0.00 sec)建用户步骤：
mysql> create user mysql identified by 'mysql.pass'; Query OK, 0 rows affected (0.00 sec) mysql> create database testDB; Query OK, 1 row affected (0.00 sec) mysql> grant all on testDB.* to mysql; Query OK, 0 rows affected (0.00 sec)
试试看。。。
成功。