I am studying openstack, in the virtual machine, after I change the 00-nova-placement-api.conf,

I want to restart httpd:

systemctl restart httpd

But I get failed:

Job for httpd.service failed because the control process exited with error code. See "systemctl status httpd.service" and "journalctl -xe" for details.

So I execute the:

systemctl status httpd.service

I get below information:

httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Wed 2017-05-31 16:50:51 CST; 24s ago
     Docs: man:httpd(8)
           man:apachectl(8)
  Process: 34969 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=1/FAILURE)
  Process: 34967 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
 Main PID: 34967 (code=exited, status=1/FAILURE)

May 31 16:50:51 controller1 systemd[1]: Starting The Apache HTTP Server...
May 31 16:50:51 controller1 httpd[34967]: httpd: Syntax error on line 353 of /etc/httpd/conf/httpd.conf: Syntax error on line 16 of /etc/httpd/con...fVersion>
May 31 16:50:51 controller1 systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
May 31 16:50:51 controller1 kill[34969]: kill: cannot find process ""
May 31 16:50:51 controller1 systemd[1]: httpd.service: control process exited, code=exited status=1
May 31 16:50:51 controller1 systemd[1]: Failed to start The Apache HTTP Server.
May 31 16:50:51 controller1 systemd[1]: Unit httpd.service entered failed state.

May 31 16:50:51 controller1 systemd[1]: httpd.service failed.
Hint: Some lines were ellipsized, use -l to show in full.

I execute the order below:

journalctl -xn

then I got the below information:

[root@controller1 ~]# journalctl -xn
-- Logs begin at Tue 2017-05-30 19:27:19 CST, end at Wed 2017-05-31 17:58:53 CST. --
May 31 17:58:48 controller1 systemd[1]: Unit openstack-nova-api.service entered failed state.
May 31 17:58:48 controller1 systemd[1]: openstack-nova-api.service failed.
May 31 17:58:49 controller1 systemd[1]: openstack-nova-api.service holdoff time over, scheduling restart.
May 31 17:58:49 controller1 systemd[1]: Starting OpenStack Nova API Server...
-- Subject: Unit openstack-nova-api.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit openstack-nova-api.service has begun starting up.
May 31 17:58:53 controller1 systemd[1]: openstack-nova-api.service: main process exited, code=exited, status=1/FAILURE
May 31 17:58:53 controller1 systemd[1]: Failed to start OpenStack Nova API Server.
-- Subject: Unit openstack-nova-api.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit openstack-nova-api.service has failed.
--
-- The result is failed.
May 31 17:58:53 controller1 systemd[1]: Unit openstack-nova-api.service entered failed state.
May 31 17:58:53 controller1 systemd[1]: openstack-nova-api.service failed.
May 31 17:58:53 controller1 systemd[1]: openstack-nova-api.service holdoff time over, scheduling restart.
May 31 17:58:53 controller1 systemd[1]: Starting OpenStack Nova API Server...
-- Subject: Unit openstack-nova-api.service has ...