I was looking to make a Raspberry Pi 3 cluster just for the fun of it and for learning a bit about how clusters work. From my research I have seen that the cluster concept follows 1 machine which is the master machine, and other worker machines. The master machine interacts with the outside world and distributes the work to the other machines, essentially increasing processing power and speed of use.
From what I have so far seen though, many of the Raspi3 Clusters I have seen are not true clusters in that they do not communicate through hardware, and all require internet connection to communicate and distribute (despite being connected through cat 6 cables and a network switch).
Is there a way to have an offline cluster like this and have only the master node connected to the internet? What would the benefits be and would this sort of machine be able to handle larger programs such as simulations, mining or even games which require a large degree of processing power? Would this also in theory speed up the unit as a whole?
If anyone has any links or info that may help it would be greatly appreciated. As stated before the main reason I wish to undertake this is simply for fun and that I think it would be a cool hardware project to work on, but if I'm gonna do the job I wanna do it properly and ensure the software is set up correctly to be a true cluster. Many thanks.