I have a container with a Laravel application that is used for development.
So I don't use an apache image, only a php 5.6 one. The process that keeps the container alive from not stopping is
php artisan serve --host=0.0.0.0
php artisan run:command
php artisan command:runServer 8282
there is no definite answer, you can run several process in a container, using supervisor
or any other process manager (https://github.com/garywiz/chaperone-docker, http://blog.zakame.net/2013/12/docker-and-daemontools-best-buddies.html...)
You can have several containers working together