Runtime Virtual Machine Recontextualization for Clouds

We extend cloud application contextualization, i.e. the dynamic configuration of a VM upon initialization, to leverage the full potential of cloud hosting by introducing the idea of recontextualization. We present a runtime cloud recontextualization mechanism to allow VM images and instances to be dynamically re-configured without restarts or downtime. The mechanism is applicable to all aspects of configuring a VM from virtual hardware to multi-tier software stacks, without the need to customize the guest VM. We present our work via a use case: the reconfiguration of a cross-cloud migratable monitoring service in a dynamic cloud environment. We discuss the details of the interoperable recontextualization mechanism, its architecture and demonstrate a proof of concept implementation through a performance evaluation. The results of this evaluation show that the solution performs adequately with an overhead of 18% of the total migration time, illustrating the feasibility of the solution.