Well I have installed apache2 on my Ubuntu VPS and it has been running fine for quite awhile until recently, the website went down, I diagnosed the system and it seems apache stopped running.
I have enabled Apache in the firewall, tried restarting but they all didn't work.
This is the error I get after trying to restart apache with systemctl restart apache2
Job for apache2.service failed because the control process exited with error code. See "systemctl status apache2.service" and "journalctl -xe" for details.
After running systemctl status apache2.service and journalctl -xe
This is the error
Failed to dump process list, ignoring: Input/output error
* apache2.service - The Apache HTTP Server
Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
Drop-In: /lib/systemd/system/apache2.service.d
`-apache2-systemd.conf
Active: failed (Result: exit-code) since Tue 2019-03-19 14:20:46 UTC; 6s ago
Process: 53591 ExecStop=/usr/sbin/apachectl stop (code=exited, status=0/SUCCESS)
Process: 48202 ExecReload=/usr/sbin/apachectl graceful (code=exited, status=0/SUCCESS)
Process: 54521 ExecStart=/usr/sbin/apachectl start (code=exited, status=1/FAILURE)
Tasks: 0 (limit: 386866)
CGroup: /system.slice/apache2.service
Mar 19 14:20:46 Mewbot systemd[54521]: Failed to attach 54521 to compat systemd cgroup /system.slice/apache2.service: No such file or directory
Mar 19 14:20:46 Mewbot apachectl[54521]: Action 'start' failed.
Mar 19 14:20:46 Mewbot apachectl[54521]: The Apache error log may have more information.
Mar 19 14:20:46 Mewbot systemd[1]: apache2.service: Control process exited, code=exited status=1
Mar 19 14:20:46 Mewbot systemd[1]: apache2.service: Failed to kill control group /system.slice/apache2.service, ignoring: Input/output error
Mar 19 14:20:46 Mewbot systemd[1]: apache2.service: Failed to kill control group /system.slice/apache2.service, ignoring: Input/output error
Mar 19 14:20:46 Mewbot systemd[1]: apache2.service: Failed to kill control group /system.slice/apache2.service, ignoring: Input/output error
Mar 19 14:20:46 Mewbot systemd[1]: apache2.service: Failed to kill control group /system.slice/apache2.service, ignoring: Input/output error
Mar 19 14:20:46 Mewbot systemd[1]: apache2.service: Failed with result 'exit-code'.
Mar 19 14:20:46 Mewbot systemd[1]: Failed to start The Apache HTTP Server.