A Comparison of Private Cloud Systems

Cloud Computing represents one of the most popular new paradigms making utility computing a reality. In recent years, this concept has received a lot of attention because of the enormous benefits it brings: for instance the capability known as elasticity permits users to change the number of machines they use according to their needs and in a timely manner. Many large companies deployed public cloud systems such as Amazon EC2 or Microsoft Azure. Even though the popularity and usefulness of cloud systems is clear, there are still concerns around the use of public clouds: availability, data safety or privacy. Because of these concerns there is a need to deploy private cloud systems. Systems that run on machines owned by the organization that requires them, offering similar services as public clouds to different parts of the organization while maintaining a large degree of trust. With the need for private cloud systems a number of software solutions appeared. We concentrate here on Infrastructure as a Service, cloud systems where users are given full access to virtual machines. These are generally Open Source and capture large interest from the public. In this paper we make a through comparison between three of the most popular open source cloud software systems and describe our experience with installing and maintaining small deployments using these three software suits.