Eucalyptus is an open-source software platform that allows organizations to build private and hybrid clouds with the same interfaces, tools, and APIs used to build public cloud environments like Amazon Web Services. It provides a framework for IT infrastructure and datacenter management by creating private clouds that are compatible with Amazon EC2 and S3. Eucalyptus is maintained by Eucalyptus Systems and provides a private cloud solution through components like the cloud controller, cluster controller, node controller, and storage controller.