ERROR! MySQL server PID file could not be found! Starting MySQL. ERROR! The server quit without updating PID file (/var/lib/mysql/vultr.guest.pid).

使用 vultr 主机安装mysql，按照文档：http://www.fancyecommerce.com/2016/04/29/linux-安装mysql5-6/

启动的时候报错

后来发现该主机默认存在下面的文件和文件夹

/etc/my.cnf
/etc/my.cnf.d/

也就是vultr主机，里面默认有mysql的配置，进而造成报错

[root@vultr mysql]# /etc/init.d/mysql  restart
 ERROR! MySQL server PID file could not be found!
Starting MySQL. ERROR! The server quit without updating PID file (/var/lib/mysql/vultr.guest.pid).

解决办法，将其删除

[root@vultr mysql]# rm -rf /etc/my.cnf
[root@vultr mysql]# rm -rf  /etc/my.cnf.d/
[root@vultr mysql]# /etc/init.d/mysql restart
 ERROR! MySQL server PID file could not be found!
Starting MySQL. SUCCESS! 

然后就启动成功了