The easiest setup of an Fn Server is just bringing up a standalone Fn container; however, the more complete architecture will be as shown here. A cluster implementation will be demonstrated at the end of this chapter. The following diagram shows the overview of the Fn architecture:
Figure 5.1: The architecture of the Fn FaaS cluster
As is the case with the common FaaS architecture, Fn also has the API gateway, which is Fn LB in the previous diagram. Fn LB is basically a load balancer. It passes through requests from the client to each Fn Server. In the Fn Server implementation, there is no separation concept of initiator and executor as there is no event bus at the core of the Fn's architecture. So, an Fn Server also acts as an executor to execute functions on its associate Docker engine.
Fn Servers connect to a Log Store, which could be a standalone or a cluster of DBMS. All data sent from an Fn function to the standard error is logged to the Log Store.
Fn UI and Fn LB are...