The cloud case study of ASCENS realizes a decentralized and resilient autonomic cloud --- a distributed software system able to execute applications in the presence of a permanently changing network and node infrastructure and thus difficulties such as leaving and joining computers, fluctuating usage, and applications with different requirements.

For the realization of this vision, ASCENS integrates cloud computing with voluntary computing and peer-to-peer computing and relies on nodes which are autonomic in their operation. In particular, nodes are self-aware of changes in load (arising either from cloud applications or from local applications external to the cloud) and in the network structure (i.e., nodes coming and going), which calls for self-healing properties.

To prevent data loss in cases where nodes drop out of the system, redundant data storage has been added. Finally, executing applications in such an environment requires a fail-over solution or self-adaptation of the cloud to provide application execution resilience.

The ASCENS methods applied to the ‚autonomic cloud‘ endows clouds with a more dynamic and open functionality while at the same time maintaining the key benefits of a cloud as a reliable and flexible approach for using third-party resources and services.

A prototypical implementation of the autonomic cloud is provided in the form of the Science Cloud Platform (SCP) which is also a tool of ASCENS.