You can start your mongod instance as a service by running this command but from the perspective of completing this course I would suggest you to stick with the process that is being taught in this course so that you don’t have any difficulty in doing the labs and the final exam questions.
It depends upon how you have installed MongoDB on your system. If you have followed the instructions mentioned in the link shared by you then yes, the
/etc/mongod.conf will be read by mongod.
Yes, the instructions laid out in the installation guide is for deploying MongoDB in a production environment. However, the course content has been designed with a different goals in mind.
Hope it helps!
Curriculum Support Engineer