mysql 启动报错 /usr/local/mysql//libexec/mysqld: Can't create/write to file '/var/run/mysqld/mysqld.pid'

centos查看mysql日志路径：/var/log/mysqld.log

可能日志过长，导致命令窗口查看不方便，可以下载到本地，查看ERROR

启动mysql

systemctl start mysqld

命令报错看不出具体启动失败的原因，查看日志后发现如下错误：

/var/log/mysqld.log错误信息为 

 /usr/local/mysql//libexec/mysqld: Can't create/write to file '/var/run/mysqld/mysqld.pid' (Errcode: 13) 120516 15:23:19 [ERROR] Can't start server: can't create PID file: Permission denied

 修改 /var/run/mysqld/权限为mysql 

chown -R mysql /var/run/mysqld

chgrp -R mysql /var/run/mysqld