Preheat over to 325 F
Score the ham in a diamond pattern, about 1/8" deep.
Place pineapple rings evenly around the ham. Use the cloves to fix them to the ham.
Place ham in a large roasting pan on a rack.
Bake covered (or in a foil tent) for about 2 hours.
In a medium saucepan, whisk together the pineapple juice, brown sugar, mustard, and vinegar.
Heat over medium, stirring often, until the liquid has reduced slighty and thickened up. This should take about 15 minutes.
Uncover the ham and baste it with the liquid in the dish.
Cook for another 30 minutes, basting a few more times while it cooks.
Remove from oven and let it rest for about 15 minutes before carving.