* httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2017-06-08 20:42:00 CEST; 7min ago
Docs: man:httpd(8)
man:apachectl(8)
Process: 12757 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=1/FAILURE)
Process: 27094 ExecReload=/usr/sbin/httpd $OPTIONS -k graceful (code=exited, status=0/SUCCESS)
Process: 12755 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
Main PID: 12755 (code=exited, status=1/FAILURE)
Jun 08 20:42:00 vz38050 systemd[1]: Starting The Apache HTTP Server...
Jun 08 20:42:00 vz38050 systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
Jun 08 20:42:00 vz38050 kill[12757]: kill: cannot find process ""
Jun 08 20:42:00 vz38050 systemd[1]: httpd.service: control process exited, code=exited status=1
Jun 08 20:42:00 vz38050 systemd[1]: Failed to start The Apache HTTP Server.
Jun 08 20:42:00 vz38050 systemd[1]: Unit httpd.service entered failed state.
Jun 08 20:42:00 vz38050 systemd[1]: httpd.service failed.
这就是“systemctl status httpd.service -l”的结果。日志看起来几乎一样。我该如何进一步调试？