Lesson 1 — Config & env

Settings live outside the code

DevOps is the work of building, shipping and running software reliably. Rule number one: settings like the port or the database address are not written into the code. They come from environment variables — named values set on the server (in Node: process.env.PORT). If one is missing, the app uses a safe default.

const region = env.REGION || "eu-west";

Note: real DevOps tools (CI servers, load balancers, Docker, Kubernetes) cannot run in your browser, so this exercise is a small plain-JS simulation of the logic those tools use. Here env is a plain object standing in for the server's environment.

Why it matters: the same build can run on a laptop, a test server and production — only the settings change.