本文主要遇到的问题，启动mysql报错：Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.
[root@oldboy ~]# service mysqld start # 重启
Redirecting to /bin/systemctl restart mysqld.service
Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.
百度了好久，经过一系列的重启，修改权限，并不能精准找到错误原因，发现有说磁盘空间不足的、有说需要删除var/lib/mysql，所有文章千篇一律。
然而，无论哪种说法，都没有什么卵用
查看mysql日志:cat /var/log/mysqld.log
提示3306端口被占用了,但是过滤并没有mysql相关进程
[root@oldboy ~]# ps aux | grep mysql
root 25791 0.0 0.0 112812 972 pts/2 R+ 18:29 0:00 grep --color=auto mysql
修改配置文件后，依旧重启报错
[root@oldboy etc]# systemctl restart mysqld
Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.
[root@oldboy etc]# systemctl restart mysql
Failed to restart mysql.service: Unit not found.
烦请路过的大佬帮忙看看，感谢万分！！！
