Partitioning applications for hybrid and federated clouds

On-demand access to computing resources asa-service has the potential to allow enterprises to temporarily scale out of their private data center into the infrastructure of a public cloud provider during times of peak demand. However, concerns about privacy and security may limit the adoption of this technique. We describe an approach to partitioning a software application (particularly a client-facing web application) into components that can be run in the public cloud and components that should remain in the private data center. Static code analysis is used to automatically establish a partitioning based on low-effort input from the developer. Public and private versions of the application are created and deployed; at runtime, user navigation proceeds seamlessly with requests routed to the public or private data center as appropriate. We present implementations for both Java and PHP web applications, tested on sample applications.