How to do SOA right? An SOA Governance Framework for the ESA Space Situational Awareness Preparatory Programme

Abstract

Service Orientation is a software design paradigm, which promises increased return on IT investments and organisational agility towards business changes. In the past years, the SOA design paradigm has been adopted by a large number of new software development projects. Many organisations are however facing difficulties in demonstrating the value of their SOA projects. This has been mainly because most of early SOA initiatives have been technology driven. This setback has led to a shift in the SOA paradigm, moving the focus from technology to SOA as a design paradigm. Organisations have in the recent years come to realise that the promised benefits of SOA, come unavoidably with the need for more coordination across the traditional boundaries of individual projects and across business lines. This need is typically addressed by establishing some level of governance in an SOA environment. Without an appropriate level of governance the SOA projects can quickly spiral to chaos and end in the undesirable state of "Wild West SOA". An SOA governance is typically defined using a set of "precepts", "processes", "roles" and "metrics", which together establish the framework for making the right decisions when doing SOA. SOA adoption impacts many aspects of funding, planning, implementation and operation of software systems. A successful SOA Governance framework must accordingly cover the complete service life-cycle as well as the service portfolio management aspects; The example of the ESA's Space Situational Awareness Preparatory Programme (SSA-PP) demonstrates how SOA and SOA Governance can be successfully applied in the context of a space programme. One of the objectives of the SSA-PP has been provision of services based on federation of assets, which are owned and governed by different participants. SOA has therefore been adopted as a suitable architectural choice for realising SSA-PP software systems. The SSA services are currently being developed in multiple parallel software development projects with European industry throughout Europe. This setup represents some challenges at system level, as each project reuses services of other projects while providing in turn its own services for reuse to others. Moreover the system level SSA capabilities can only be realised through orchestration of the services of multiple projects. The interdependency of the service development projects is typical for a mature SOA and gives raise to the need to more strict coordination when it comes to introduction of new services vs service reuse, standardisation of service contracts, use of common data models, governance of service reuse, service ownership and service change management. In order to address this eminent need for coordination, The SSA Preparatory Programme SOA Governance Framework has been developed in 2011 in a joint effort by the European Space Agency (ESA) and industrial experts.