dashboard conflict with php,which result in httpd.sevice restart failed

When I install openstack into redhat 7, I find one strange thing.
When I install dashboard firstly and then install php, httpd.sevice restart failed.
error info:
httpd[32735]: AH00526: Syntax error on line 31 of /etc/httpd/conf.d/php.conf:
httpd[32735]: Invalid command 'php_value', perhaps misspelled or defined by a module not included in the server configuration

When I install php firstly and then install dashboard, httpd.sevice still restart failed.
error info:
 httpd[20260]: AH00526: Syntax error on line 1 of /etc/httpd/conf.d/openstack-dashboard.conf:
 httpd[20260]: Invalid command 'WSGIDaemonProcess', perhaps misspelled or defined by a module not included in the server configuration

This is a very strange thing. I think it might be http's problem, but I don't know how to figure it out.
ps:If I just only install php or dashboard, httpd.sevice could restart successfully.