Politecnico di Bari
The advent of the cloud computing paradigm offers different ways both to sell services and to exploit external computational resources according to a pay-per-use economic model. Nowadays, cloud computing clients can buy various forms of IaaS, PaaS, and SaaS from cloud providers. Besides this form of pay-per-use, the perspective of cloud federation offers further business opportunities for small/medium providers which hold physical datacenters. Considering the cloud computing ecosystem, besides large cloud providers, also smaller ones are becoming popular even though their own virtualization infrastructures (i.e., deployed in their datacenters) cannot directly compete with the bigger market leaders.