Dockerized DotNet API with Load Balancing

A simple .NET API application running two instances behind an NGINX load balancer using Docker Compose.

How to Run (Using Docker Compose)

1. Build and start the containers:

   docker-compose up --build -d

2. Access the API via load balancer:
   Open your browser and visit: http://localhost:2524

   • This endpoint is served through NGINX and will load balance requests between two API instances.

3. Stop the containers:

   docker-compose down

4. Rebuild the images if changes are made:

   docker-compose up --build -d

Load Balancing with NGINX

This project uses an nginx.conf configuration to set up a round-robin load balancer:

upstream dotnet_apis {
    server api1:8080;
    server api2:8080;
}

server {
    listen 80;

    location / {
        proxy_pass http://dotnet_apis;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

Every time you refresh http://localhost:2524, NGINX forwards the request to either api1 or api2 in a round-robin manner.

Project Structure

Dockerized-DotNetAPI-LoadBalanced/
│-- Controllers/
│   └── HomeController.cs
│-- Properties/
│   └── launchSettings.json
│-- Program.cs
│-- Dockerfile
│-- docker-compose.yml
│-- nginx.conf
│-- Dockerized-DotNetAPI-LoadBalanced.csproj
│-- appsettings.json
│-- appsettings.Development.json

Environment Configuration

By default, the API runs in Production mode as set in Program.cs and project settings.

Each instance identifies itself using the container name (api1, api2) retrieved at runtime.

Logs

Currently, logs are printed to the console. You can view them using:

docker-compose logs -f

Notes

• Demonstrates container-based load balancing using Docker Compose and NGINX.
• Each API instance returns its identity based on container hostname.
• Useful for learning how to scale .NET services with Docker and basic load balancing setup.

Ports Used

• 2504: API instance 1 (mapped but not directly accessed)
• 2514: API instance 2 (mapped but not directly accessed)
• 2524: Load balancer (NGINX) – main access point

Make sure Docker is installed and these ports are available.