Architecture Challenges for Internal Software Ecosystems: A Large-Scale Industry Case Study

The idea of software ecosystems encourages organizations to open software projects for external businesses, governing the cross-organi-zational development by architectural and other measures. Even within a single organization, this paradigm can be of high value for large-scale decentralized software projects that involve various internal, yet self-contained organizational units. However, this intra-organizational decentralization causes architecture challenges that must be understood to reason about suitable architectural measures. We present an in-depth case study on collaboration and archi-tecture challenges in two of these large-scale software projects at Siemens. We performed a total of 46 hours of semi-structured interviews with 17 leading software architects from all involved organizational units. Our major findings are: (1) three collaboration models on a continuum that ranges from high to low coupling, (2) a classification of architecture challenges, together with (3) a qual-itative and quantitative exposure of the identified recurring issues along each collaboration model. Our study results provide valuable insights for both industry and academia: Practitioners that find them-selves in one of the collaboration models can use empirical evidence on challenges to make informed decisions about counteractive mea-sures. Researchers can focus their attention on challenges faced by practitioners to make software engineering more effective