Flexible Cloud Computing by Integrating Public-Private Clouds Using OpenStack

Organizations today are moving towards cloud computing in order to reduce their upfront capital expenses. Typically, organizations have limited infrastructure with which they create a private cloud. If the number of user requests go beyond those that can be supported by the limited infrastructure, new user requests are denied. In order to overcome this situation, in this paper, we suggest building a cost aware flexible cloud. We integrate the organization's private cloud with a public cloud. For new requests that need to be hosted on the public cloud, the organization pays rental costs. When the number of requests at the organization goes below a certain threshold, some instances already migrated to the public cloud can be migrated back to the private cloud for reducing the rental costs. We provide solutions to both these issues and have demonstrated an implementation over the open-source Open Stack framework.