http://web.mit.edu/stardev/cluster/
Multiple Clusters – Currently, StarCluster only supports launching a single cluster on ec2. In theory, the software should be able to START multiple clusters but it’s not equipped to handle the accounting on which nodes belong to which cluster after the initial startup. This means things like listing the nodes, terminating a particular cluster, etc will not work. Support for the correct account of multiple clusters should come in future versions.
Dynamic Load Balancing – Support for a dynamically resizing cluster on ec2. Integrating the Service Domain Manager (SDM) and Hedeby software products from SUN into the AMI will allow ec2 nodes to easily be added to the Sun Grid Engine queue. This means you could theoretically start a single node cluster and as the load increases, ec2 nodes would be launched, added to the cluster, used for computation, and then removed when they’re idle. The impact of this would be to significantly lower the cost of using EC2 by only having one node up 24/7 and adding/removing nodes as needed.