Dry dog food stores well and there's no reason not to buy in bulk when on sale. About a year worth of shelf life is pretty reasonable with most kibble. With good packaging you don’t need any special way of storing it, just keeping it in a cool dry place away from bugs and check the integrity of the bag every once in a while. Better yet, put the bag in a metal or plastic container. If rats and other pests don’t get to it, the food should easily last 12 months.
About dog food. Not all dog food is alike. Cheap kibble like Pedigree will keep your dog alive but its not nearly as good as some other choices. The key (and expensive) ingredient in dog food is meat. Chicken, turkey, lamb, any animal will do but the meat protein content is the most important ingredient. Read the label and make sure your dog food has at least 20% of meat in it. Especially during the first tow years of life when the dog is growing, make sure you feed it quality food if you can afford it. If it ever comes down to rationing your dog food you could mix quality dog food with rice half and half. It wouldn’t be as good but you can stretch good kibble a bit like that if needed.
You can feed your dog the same food you store but it makes more sense to just stock up on kibble when on sale. Besides, during a real emergency it wouldn’t make sense to spend precious food on the dog. A few extra bags avoids that kind of hard decision. At least for a few months!