You can find Coke, Sprite, and Fanta in most shops; Diet Coke is found in fewer shops.
Several stores will serve beer and you can also buy alcohol at some of the larger supermarkets, although you may find it difficult to buy alcohol on Fridays because of religious observance. Most Kazakhs will drink alcohol, even though they will say that it isn't appropriate according to Islam, but they may not drink on Fridays.