First, I think one absurd thing builders do is pepper roofs with hundreds of UGLY vents and pipes. One small house near me has 16 piece of junk out the roof, everyone a future leak. One 3" pipe will handle most houses, and certainly one 3" hole is cheaper than 16. And you can go out the sidewall, if you follow the code. Then we use fire stop eave vents and a continous ridge vent. A perfect roof.
I use that roof, and its a problem. go out the sidewall after talking to the inspector, tie vents in the attic. NOt possible - I have made a tight hole with a hole saw and used a small steel or neoprene ring [like the top inch of that pic] and super siliconed in, under, and around it and then used some elastomeric mastic over it all, and painted it to match the roof. stay off the ribs. fiberglas tape in the mastic makes it bombproof