The original idea for a microservice was something small and independent that could be replaced in a couple of days.
These days we end up with distributed monoliths that are called a set of microservices.
Independent means that it could be deployed in multiple places.
Lets use a practical example. We have some images that we need thumbnails for. Images are stored in an S3 bucket. An ideal microservice would watch for images being created then create the thumbnails.
This could be configured via a pulumi script. By giving a base prefix all the parts could be configured as a set of serverless functions.
For a sufficiently large company could probably mine a number of these utilities from systems that already exist.
Developer Rants 