Cloud computing is an attractive computing model since it allows
for resources to be provisioned according on a demand basis, i.e., cloud users
can rent resources as they become necessary. This model motivated several
academic and non-academic institutions to develop open-source cloud
solutions. This paper presents and discusses the state-of-the of open-source
solutions for cloud computing. The authors hope that the observation and
classification of such solutions can leverage the cloud computing research
area providing a good starting point to cope with some of the problems
present in cloud computing environments.