If one needs to dynamically update the resources on a running applications the below link would definitely help in how to achieve this effect.
http://www.ibm.com/developerworks/websphere/library/techarticles/0502_botzum/0502_botzum.html
A good explanation of cell node and cluster is provided in the below given link https://itdevworld.wordpress.com/2009/05/03/websphere-c...