centos7 httpd程序的错误

-- Unit httpd.service has begun starting up.
Jul 01 21:13:02 localhost.localdomain httpd[3234]: httpd (pid 5103) already running
Jul 01 21:13:02 localhost.localdomain kill[3251]: kill: cannot find process ""
Jul 01 21:13:02 localhost.localdomain systemd[1]: httpd.service: control process exited, code=exited status=1
Jul 01 21:13:02 localhost.localdomain systemd[1]: Failed to start The Apache HTTP Server.
-- Subject: Unit httpd.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit httpd.service has failed.

解决方法：

重启网络：

systemctl stop network
systemctl start network.service 有点想不通是什么问题