As part of the introduction to this chapter, we looked at the difference between stateful and stateless microservices. The Service Fabric application templates available are then further divided into Reliable Services (stateful/stateless) and Reliable Actors. When to use which one is something that will depend on the specific business requirement of your application.

To put it simply though, if you wanted to create a service that should be exposed to many users of your application at any one time, a Reliable Service would probably be a good fit. Think of a service exposing the latest exchange rates that can be consumed by many users or applications at once.

Again, looking back to the introduction of this chapter, we used the example of an online web store with a shopping cart. A Reliable Actor could be a good fit for every customer buying items, so you could have a shopping cart actor. The Reliable Actor as part of the Service Fabric framework is based on the Virtual Actor pattern. Have a look at the article on the Virtual Actor pattern at http://research.microsoft.com/en-us/projects/orleans/.

To show you how easy it is to create a microservice using a stateless actor service as an example, we will use Visual Studio to publish a service to the Service Fabric cluster and call that service from a console (client) application.