（Apache 2.4 / centOS 7）
[root@localhost ~]# service httpd start Redirecting to /bin/systemctl start httpd.service Job for httpd.service failed. See 'systemctl status httpd.service' and 'journalctl -xn' for details. [root@localhost ~]# service httpd status Redirecting to /bin/systemctl status httpd.service httpd.service - The Apache HTTP Server Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled) Active: failed (Result: exit-code) since Sat 2015-12-05 08:50:58 IRST; 4min 22s ago Process: 3858 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=1/FAILURE) Process: 3856 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE) Main PID: 3856 (code=exited, status=1/FAILURE) Dec 05 08:50:58 localhost.localdomain systemd[1]: Starting The Apache HTTP Server... Dec 05 08:50:58 localhost.localdomain systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE Dec 05 08:50:58 localhost.localdomain kill[3858]: kill: cannot find process "" Dec 05 08:50:58 localhost.localdomain systemd[1]: httpd.service: control process exited, code=exited status=1 Dec 05 08:50:58 localhost.localdomain systemd[1]: Failed to start The Apache HTTP Server. Dec 05 08:50:58 localhost.localdomain systemd[1]: Unit httpd.service entered failed state. 我可以使用httpd -k start来启动它，服务有什么问题？