Orchestrating microservices

Question

What is the standard pattern of orchestrating microservices?

If a microservice only knows about its own domain, but there is a flow of data that requires that multip

Answer 1

So, how is orchestration of microservices different from orchestration of old SOA services that are not “micro”? Not much at all.

Microservices usually communicate using http (REST) or messaging/events. Orchestration is often associated with orchestration platforms that allow you to create a scripted interaction among services to automate workflows. In the old SOA days, these platforms used WS-BPEL. Today's tools don't use BPEL. Examples of modern orchestration products: Netflix Conductor, Camunda, Zeebe, Azure Logic Apps, Baker.

Keep in mind that orchestration is a compound pattern that offers several capabilities to create complex compositions of services. Microservices are more often seen as services that should not participate in complex compositions and rather be more autonomous.

I can see a microservice being invoked in an orchestrated workflow to do some simple processing, but I don’t see a microservice being the orchestrator service, which often uses mechanisms such as compensating transactions and state repository (dehydration).