1.现场：
[root@ha02 ~]# mysqladmin -u root password 'root'
mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'root'@'localhost' (using password: NO)'
此时也无法修改密码
2.解决步骤
[root@ha02 ~]# service mysqld stop
Stopping mysqld: [ OK ]
[root@ha02 ~]# mysqld_safe --skip-grant-tables &
[1] 6249
[root@ha02 ~]# 141128 07:13:16 mysqld_safe Logging to '/var/log/mysqld.log'.
141128 07:13:16 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
[root@ha02 ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.66 Source distribution
Copyright (c) 2000, 2012, 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 password=PASSWORD("root")where user="root";
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye