AH00534: httpd: Configuration error: No MPM loaded

Issue

• Apache httpd サービスの開始に失敗し、以下のエラーが発生します。

# systemctl status -l httpd.service
httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled)
   Active: failed (Result: exit-code) since Tue 2016-10-18 10:16:09 IST; 7s ago
     Docs: man:httpd(8)
           man:apachectl(8)
  Process: 23970 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=1/FAILURE)
  Process: 23967 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
 Main PID: 23967 (code=exited, status=1/FAILURE)

Oct 18 10:16:09 localhost httpd[23967]: AH00534: httpd: Configuration error: No MPM loaded.
Oct 18 10:16:09 localhost systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
Oct 18 10:16:09 localhost kill[23970]: kill: cannot find process ""
Oct 18 10:16:09 localhost systemd[1]: httpd.service: control process exited, code=exited status=1
Oct 18 10:16:09 localhost systemd[1]: Failed to start The Apache HTTP Server.
Oct 18 10:16:09 localhost systemd[1]: Unit httpd.service entered failed state.