As a result of the rapid growth of Cloud Computing, several Cloud middleware solutions for the creation and automated management of virtual appliances have been released. Generally, these solutions offer some predefined scheduling policies to manage the provider infrastructure, but additional tuning of the policies is often needed to fully align their behavior with the provider interests. However, current middleware solutions do not offer ways to do this without stopping and recompiling the middleware. This paper proposes a solution that separates scheduling policies from the managers that interpret them, to allow the behavior of the management system to be changed without re-coding the managers. In this way, the middleware can adapt to changing requirements by disabling policies or replacing old policies with new ones without shutting down the system. We propose a new policy language for the definition of management policies and we enable the EMOTIVE Cloud middleware to use these policies by integrating in the middleware the needed policy management framework for parsing and generating code on demand. We demonstrate with real experiments that our policy management framework mimics the expressiveness of scheduling policies in real Cloud middleware and provides more expressiveness if needed. The overhead of the policy management framework is low, but its performance degrades, especially in large datacenters, due to the low scalability of the EMOTIVE monitoring solution.

This work is supported by the Ministry of Science and Technology of Spain and the European Union (FEDER funds) under contract TIN2012-34557, and by the Generalitat de Catalunya under contract 2009-SGR-980.

Peer Reviewed