This reference architecture designs, develops and deploys a simple distributed microservice architecture on Red Hat JBoss Enterprise Application Platform 7.0 on top of OpenShift. The application architecture is based on the design laid out and explained in depth in the reference architecture document on EAP Microservice Architecture.

The OpenShift environment includes a highly available master and two nodes. An alternatively trial configuration is described to use quick installation and configure a single stand-alone master, which is not intended for use in a production environment. The application is set up as a single OpenShift project, called msa.

This project includes six services, where two of these are database services based on the standard and supported MySQL image. The remaining four images are based on the supported JBoss EAP xPaaS image and rely on the Source to Image (S2I) functionality to build and deploy. The EAP images are customized for two of these services to add a MySQL datasource.

All OpenShift services can be configured and scaled with the desired number of replicas. In a default OpenShift installation, the nodes are the only targets for service deployment. However, the masters can also be configured as scheduleable in order to host service replicas.

The presentation service is the only entry point to the application and serves HTML to the client browser over HTTP. This web tier is stateless, and can therefore be replicated without concern for multicast communication or alternative EAP clustering setup. This services relies on the product, sales, and billing services, while the first two in turn rely on the MySQL product-db and sales-db services.