Preheat oven to 425°F and line a large sheet pan with parchment paper.
In a small bowl, whisk together balsamic vinegar, honey, 1 tablespoon olive oil, minced garlic, and rosemary.
Pat the pork tenderloin dry and season with salt and pepper. Toss the potatoes with the remaining 1 tablespoon olive oil, salt, and pepper; spread them on the pan and roast for 15 minutes.
Remove the pan from the oven, turn the potatoes, place the pork in the center, and arrange the green beans around it.
Brush half of the balsamic glaze over the pork tenderloin.
Roast for 20-25 minutes, brushing pork with remaining glaze halfway through, until pork reaches an internal temperature of 145°F.
Remove from oven, tent with foil, and let rest for 5 minutes before slicing and serving.