Carrying gasoline for generator

Just wondering how much gasoline is legal to carry for the generator and how do you have to store it or secure it?

Also I'm looking at a fuel pump kit that would allow me to have an actual auxiliary fuel tank that's not gravity-fed or any of that.

There is no regulation against having such a tank is there? Or is there any regulation against the number of gallons you can carry in that tank?

I actually have a spare fuel tank that I could mount on the side of my truck.

 

Can you have a separate mounted fuel tank carrying more than 8 gallons?

 

I would love to have a diesel generator and I'm not afraid to spend the money but from what I understand they're much much louder than a regular inverter generator. And I haven't really checked them for size.

Does anyone have a diesel generator that they're running?

 

Well I have an aluminum tank that was for diesel from another truck. Is there any reason I couldn't use that? I also have a smaller gasoline tank from a gasoline truck that I had but I would rather use the aluminum tank if I could.