启动MySQL报错：

[root@localhost log]# service mysql start

Starting MySQL...The server quit without updating PID file [FAILED]/data/localhost.localdomain.pid).

查看error.log:

log-error=/var/log/error.log

忽略warning，看error

2020-12-11T14:15:20.074345Z 0 [ERROR] Unix socket lock file is empty /tmp/mysql.sock.lock.

2020-12-11T14:15:20.074362Z 0 [ERROR] Unable to setup unix socket lock file.

2020-12-11T14:15:20.074377Z 0 [ERROR] Aborting

解决办法：

进入/tmp/查看mysql.sock.lock，文件大小为0，直接删除该文件rm  -rf mysql.sock.lock再启动mysql：service mysql start。即可启动成功。

[root@localhost log]# service mysql start

Starting MySQL.                                            [  OK  ]