Operations

CloudStack is a platform for building and managing scalable infrastructures and is written entirely in Java. You will find detailed instructions for administration, installation, and API development on the CloudStack site [7]. Currently, CloudStack supports commercial hypervisors from Citrix, VMware, and Oracle, as well as XenServer and KVM.

CloudStack provides three interfaces from which to choose: web, command line, and the REST API. The CloudStack architecture consists of several components. The Compute Controller controls computing power, the Network Controller controls the virtual networks, and the Storage Controller takes care of the Block Storage management.

The three basic components can access the underlying physical hardware directly. The CloudStack Orchestration Engine, in turn, relies on these components to control the cloud infrastructure. The Cloud Stack API accepts commands from the web interface or the command line via REST and forwards them for processing to the Orchestration Engine. The web interface is a modern, Ajax-based web GUI, which greatly simplifies the management of the cloud infrastructure stack. The GUI visualizes components such as CPU, storage, IP pool, and memory in real time.

Conclusions

In recent weeks and months, the OpenStack project has enjoyed plenty of attention in the media. What is missing in OpenStack, however, is direct AWS support. In contrast, the younger CloudStack project offers AWS support, having been emancipated last year by Citrix, and has established itself as an Apache top-level project.

CloudStack is the undisputed leader not only in terms of supported cloud APIs but also in terms of supported hypervisor platforms, including Hyper-V in the near future. Additionally, CloudStack supports the Citrix Cloud Platform and VMware. The Java software is more coherent than OpenStack and, besides the command-line interface and the REST API, includes an attractive web interface out of the box.In terms of flexibility, CloudStack is thus the top-ranking open source IaaS system, at least in theory.

However, whatever solution you ultimately decide to use, you cannot rely on theory alone. In cloud computing more than anywhere else, it is a definite advantage for a solution to have a high degree of openness. You can find a very readable discussion of this aspect in a posting on the Open Nebula blog [8].