Last weekend, I gave it a quick POC of evaluating setting up hadoop on a few raspberry Pis. However, there was one Pi who only has  256MB RAM and also, the accessories were not complete and it was not perfect as I expected. Then I went ahead and bought a few gears from Amazon, a power outlet that has 12 sockets with rotating connector which will totally handle the raspberry pi cluster, switch, laptop..etc. Also, I purchase another raspberry pi from Amazon, it is from the Canakit and contains a 2nd generation pi, power supply and a case, which I think is a nice bundle.