Infrastructure as Code (IAC) Cookbook

Simulating a networked three-tier architecture app with Vagrant

Vagrant is a great tool to help simulate systems in isolated networks, allowing us to easily mock architectures found in production. The idea behind the multiple tiers is to separate the logic and execution of the various elements of the application, and not centralize everything in one place. A common pattern is to get a first layer that gets the common user requests, a second layer that does the application job, and a third layer that stores and retrieves data, usually from a database.

In this simulation, we'll have the traditional three tiers, each running CentOS 7 virtual machines on their own isolated network:

• Front: NGINX reverse proxy
• App: a Node.js app running on two nodes
• Database ...