tl;dr In PARL approach, a microservice is defined by business as "Persona takes Action on a Resource from a Location". This definition helps a Software Architect to clearly lay out technical specifications for maximum server utilisation in the form of a microservice table. This microservice table helps a Developer implement the requirements into tangible entities.
The software development requirements laid down by an organization are driven by domain knowledge towards the goal of achieving the "mission statement" of an organization. The software development team implements the requirements towards the goal of maximum server utilisation in a quick and an automated fashion. These goals are aligned only if the software development requirements are unambiguosly understood by both business organization and software development teams. The alignment of business and software development goals is even more necessary in today's era of microservices. While the software development team can achieve very high server utilisation by developing microservices ("single purpose" artefacts), the business organisation will define the boundary of microservice.
This article presents PARL approach to arrive at a definition of the microservice that brings the alignment of business and software development teams easily.
For the complete article, read microservice.md.