FAQs

Eucalyptus is a private cloud-computing platform that implements the Amazon specification for EC2, S3, and EBS. Eucalyptus conforms to both the syntax and the semantic definition of the Amazon API and tool suite, with few exceptions. Along with providing a REST and SOAP interface compatible with Amazon AWS, Eucalyptus also exposes administrative functionalities (e.g., user management, storage configuration, network management, hypervisor configuration, etc.) for managing and maintaining the cloud. Our implementation of the specification, however, is undoubtedly different than Amazon's implementations. These differences are related to several engineering design decisions. Our primary goal is to provide an open-source software tool for community distribution that is highly scalable and extensible, as well as easy to install and maintain.

The intention is to be able to support multiple cloud computing interfaces using the same "back end" infrastructure. EC2 seemed to be the best documented of the available choices at the time we began development and also the most commercially successful so we chose to implement it first. The interface module, however, can be replaced without changing the rest of the system.

No. In a commercial public cloud, clients pay for their use with a credit card. Eucalyptus is designed to work in an environment where machines are available to a user community that accesses them via logins. Because user accountability usually must be ensured by the system administrators in such an environment, we have developed a "cloud administrator" interface for Eucalyptus that is more analogous to common practice in a setting without fees.

Eucalyptus targets Linux systems that use Xen (versions 3.*) and KVM for virtualization. We provide binary packages for several Linux distributions and also offer a source package as well.

Amazon implements "availability zones" to allow users some degree of control over instance placement. Specifically, EC2 users can choose to host images in different availability zones if they wish to try and ensure independent failure probabilities. Amazon, presumably, takes steps to insulate instances in separate availability zones from correlated failure (e.g., a single power outage that takes out a data center).

Under Eucalyptus, the abstraction is slightly different. Each availability zone corresponds to a separate cluster within the Eucalyptus cloud. The advantage is that the networking within a single availability zone can be made much faster (i.e., it uses the cluster's private network in native mode). For allocations that span clusters, the technology Eucalyptus uses to implement a private network for each allocation imposes a substantial performance penalty.

Thus the two are similar in that cloud allocations to separate availability zones do reduce the chance of correlated failure. They are different, however, in that under Eucalyptus, each availability zone is restricted to a single "machine" (e.g., cluster) where at Amazon, the zones are much broader.