The fourth industrial revolution (Industry 4.0) anticipates unplanned changes of production processes. Production changes may trigger synthesis, and preferably optimization, of architecture design decisions, such as service deployment and composition, plant layout synthesis, or production planning. This paper investigates possibilities of finding valid and optimal architectural design decisions while respecting Industry 4.0 specifics. To obtain an overview of possibilities for the architecture synthesis and optimization in the Industry 4.0 context, we developed a taxonomy describing architectural models, design decisions, and optimization possibilities. The developed taxonomy should serve as a guideline for comparing different possibilities (e.g., application of different optimization algorithms) and selecting the appropriate one for the given context. Furthermore, we conduct the literature review and map the research works to the taxonomy. Therefore, we identify research trends and research gaps by classifying the state-of-the-art. This allows researchers finding interesting but uncovered topics.