The benefits of service choreography for data-intensive computing

Abstract

As the number of services and the size of data involved in workflows increases, centralised orchestration techniques are reaching the limits of scalability. In the classic orchestration model, all data pass through a centralised engine, which results in unnecessary data transfer, wasted bandwidth and the engine to become a bottleneck to the execution of a workflow. Choreography techniques, although more complex to model offer a decentralised alternative and are the optimal architecture for data-centric workflows; data are passed directly to where they are required, at the next service in the workflow.While orchestration is the dominant architectural approach, there are relatively few choreography languages and even fewer concrete implementations. This papers contributions are twofold. Firstly we argue the case for choreography in data-intensive computing, and demonstrate through workflow patterns the advantages in terms of scalability when a choreography architecture is adopted. Secondly we introduce the Light Weight Coordination Calculus (LCC), a type of process calculus used to formally define choreographies, and the OpenKnowledge framework, a choreography-based architecture, providing the functionality for peers to coordinate in an open peer-to-peer system. Through LCC and the OpenKnowledge framework we practically demonstrate how choreography can be achieved in a lightweight manner with a comparatively simple process language.

A methodology to define QoS and SLA requirements in service choreographies

“…Different from orchestrations, choreographies don't have a single point of control or coordination [3]. Choreographies tend to be more efficient than orchestrations because the probability to have a bottleneck in the system is reduced [5].…”

Choreographing Web Services with Semantically Enhanced Scripting

“…The XLCC language was derived from LCC, which is a compact declarative language [5] deployed in the OpenKnowledge project for describing and executing WS choreography between peers. LCC choreography specifications are also executable, but until now LCC interpreters have only been produced for peer-to-peer and service architectures, not for a Web environment.…”

A process partitioning technique for constructing decentralized web service compositions

“…The centralized service composition has advantages of simple topological structure and high maintainability, so it has been widely adopted in applications, such as Web Services Business Process Execution Language (BPEL)–based applications. However, in some cases, the centralized service composition may have heavy network traffic to make its mediator become a bottleneck . On the other hand, due to its features, the decentralized service composition can mitigate the issues of the centralized service composition.…”

“…On the other hand, due to its features, the decentralized service composition can mitigate the issues of the centralized service composition. Decentralized service compositions have received growing attention, and a number of issues have been discussed, such as the decentralized system design, implementation, deployment, application, and analysis . It was shown that, if a decentralized composition is built and deployed properly, the composition can achieve better performance and reduce network traffic when compared with the corresponding centralized composition .…”