Open source software has provided the foundation for many cloud
  computing implementations:

  - OpenNebula is an open-source toolkit to easily build any type of
  cloud: private, public and hybrid. OpenNebula has been designed to be
  integrated with any networking and storage solution and so to fit into
  any existing data center. OpenNebula orchestrates storage, network and
  virtualization technologies to enable the dynamic placement of
  multi-tier services (groups of interconnected virtual machines) on
  distributed infrastructures, combining both data center resources and
  remote cloud resources, according to allocation policies.

  - Eucalyptus began as a research project in the field of high
  performance computing (HPC) under the direction of Professor Rich
  Wolski in the Computer Science Department at the University of
  California, Santa Barbara. Eucalyptus is an open-source software
  infrastructure for the implementation of cloud computing on computer
  clusters which provides an interface that is compatible with the
  Amazon EC2 service. It is also the core element of the Ubuntu
  Enterprise Cloud (UEC), a cloud computing module provided with
  distributions of the Linux-based Ubuntu operating system.

  - Tashi is an open-source project being incubated at Apache that aims
  to build a software infrastructure for cloud computing on massive
  internet-scale datasets (a.k.a. 'Big Data'). The idea is to build a
  cluster management system that enables the Big Data that are stored in
  a cluster/data center to be accessed, shared, manipulated, and
  computed on by remote users in a convenient, efficient, and safe
  manner. Tashi is primarily a system for managing virtual machines.

  In this presentation, I'll start talking about some of the basic
  concepts related to Cloud Computing and Virtualization. After that,
  I'll present the three tools, showing their Cloud API and main
  features. A brief comparison among the tools and install procedures
  will also be presented.