You will have an ice bucket in your room. If you bring along a cooler, your room steward will keep it filled with ice.
You can get ice for an individual drink in the lido deck buffet or at any bar on the ship..
I bring along an insulated cup or you can buy a logo one in the ships store.
i've never taken drinks on board, but i had friends sneak liquor (vodka) on the ship before in water bottles. they would order juice through room service and then go up to the lido deck (where the buffet is served) and get cups to fill with ice from the drink machines. i don't know if they'll bring you a bucket of ice or not, but you can always get ice from the deck. hope this helps some.
Your ice bucket is also filled daily by your room steward. The ice keeps pretty much all day and your steward will refill the bucket in the evening too if they notice that you have used it. For coolers, etc, as long as there is no alcoholic beverages in them, you can carry on a cooler as you embark. The security guards will ask that you open it and show them but Carnival does allow the coolers.
Grand Princess 112704