Eucalyptus is an open source software to build private and hybrid cloud in Amazon Web Services (AWS).
It stands for Elastic Utility Computing Architecture for Linking Your Programs To Useful Systems.
We can create our own datacenter in a private cloud by using Eucalyptus. It makes use of pooling the computing and storage resources to scale up the operations.
In Eucalyptus, we create images of software applications. These images are deployed to create instances. These instances are used for computing needs.
A Eucalyptus instance can have both public and private ip addresses.