操作系统为centos，网站突然连接不上数据库,于是朋友直接重启了一下服务器。进到cli模式下，执行 service myqsld start 发现还是提示"mysql deamon failed to start"错误信息。

# /etc/init.d/mysqld start

MySQL Daemon failed to start.

Starting mysqld: [FAILED]

查看mysqld的log文件

#less /var/log/mysqld.log

141201 11:35:20 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

141201 11:35:43 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

141201 11:35:43 [Warning] '--default-character-set' is deprecated and will be removed in a future release. Please use '--character-set-server' instead.

141201 11:35:43  InnoDB: Initializing buffer pool, size = 8.0M

141201 11:35:43  InnoDB: Completed initialization of buffer pool

141201 11:35:43  InnoDB: Started; log sequence number 0 44233

141201 11:35:43 [ERROR] Can't start server: Bind on TCP/IP port: Permission denied

141201 11:35:43 [ERROR] Do you already have another mysqld server running on port: 12345 ?

141201 11:35:43 [ERROR] Aborting

说明应该是SELINUX的权限限制了，需要关掉selinux

查看当前配置信息.

# getenforce

Enforcing

就表明SELinux已经启用.只需要关闭即可。

关闭方法：

/usr/sbin/setenforce 0（0|1 开|关）

或者

setsebool ftpd_disable_trans 1