Discovering how to configure NGINX

A project exploring the main roles that NGINX can play:

• Web server — serves static files
• Reverse proxy — hides the backends behind a single entry point
• Load balancer — spreads traffic across several identical instances
• Cache manager — stores backend responses to avoid hitting them every time
• Traffic compressor — gzip compression of text responses
• Secure entrypoint — HTTPS termination

---

Full explainations on my notes here:

NGINX configuration

---

Architecture

A single NGINX instance sits in front of three identical containers running the same Express app. NGINX terminates TLS, compresses responses, caches them, and load-balances incoming requests across the three backends.

                          ┌──────────────────────────────┐
                          │            NGINX             │
   Browser  ── :443 ───▶  │  TLS · gzip · cache · proxy  │
            (HTTP→HTTPS)  │        load balancer         │
                          └───────────────┬──────────────┘
                                          │  least_conn
                 ┌────────────────────────┼────────────────────────┐
                 ▼                        ▼                        ▼
          webapp1 :3001            webapp2 :3002            webapp3 :3003
          (Express, Docker)        (Express, Docker)        (Express, Docker)

---

Project structure

.
├── README.md
├── logo/                     # source logos illustrating each NGINX role
└── webapp/
    ├── Dockerfile            # builds the Node.js image
    ├── docker-compose.yaml   # runs 3 instances of the same image
    ├── package.json
    ├── package-lock.json
    ├── server.js             # Express server (reads APP_NAME / HOST_PORT)
    └── public/               # static files served by Express
        ├── index.html
        ├── style.css
        ├── script.js
        └── images/

---

Preview

---

Prerequisites

• Docker and Docker Compose
• NGINX installed on the host (sudo apt install nginx on Debian/Ubuntu/Mint)

---

Getting started

1. Build and run the three web app instances

cd webapp
docker compose up --build

A single image is built once and reused by all three services. Each container receives a different APP_NAME and HOST_PORT via environment variables and is published on a distinct host port:

Service	Container port	Host port
webapp1	3000	3001
webapp2	3000	3002
webapp3	3000	3003

You can verify each instance directly: http://localhost:3001, :3002, :3003.

2. Configure NGINX

Copy the site configuration into /etc/nginx/sites-available/webapp, enable it, and disable the default site to free port 80/8080:

sudo ln -s /etc/nginx/sites-available/webapp /etc/nginx/sites-enabled/
sudo rm -f /etc/nginx/sites-enabled/default
sudo mkdir -p /var/cache/nginx/webapp
sudo nginx -t
sudo systemctl reload nginx

3. Open the app through NGINX

http://localhost:8080 (or https://localhost once TLS is configured).

---

Clone this repository alone

git clone git@github.com:DevCTx/Nginx.git

---

Submodule of DevOps Repository

This repository is used as a submodule in PART2-Fundamentals of my DevOps repository: https://github.com/DevCTx/DevOps

When cloning the parent DevOps repository, include this submodule with:

git clone --recurse-submodules git@github.com:DevCTx/DevOps.git