Preheat oven to 325 degrees. Grease and flour 10" tube pan or 12 cup Bundt pan. Sprinkle nuts over bottom of pan. Mix together yellow cake mix, vanilla pudding, eggs, water, oil and rum. Pour batter over nuts and bake for 1 hour. Cool for 10 minutes. Invert onto serving plate and with a wooden skewer or fork, poke holes in cake all around the top. Make sure you don't poke all the way to the serving platter so that your glaze doesn't leak out onto the platter.
For glaze, melt butter in a saucepan. Stir in water and sugar and boil for 5 minutes. Remove from heat and stir in rum. Spoon glaze all over the cake until glaze is completely used up. Chill cake.