Docker Compose vs Dockerfile for Deployment

You know you need to containerize your code. But should you use a single Dockerfile, or configure a `docker-compose.yml`? Here's the distinction and when to use highly automated PaaS deployments.

Dockerfile: The Blueprint

A Dockerfile tells Docker how to build an image. It defines the base OS, copies in your code, installs dependencies, and declares the start command. For 90% of microservices and standalone web apps, a single `Dockerfile` is all you need.

Docker Compose: The Orchestrator

A `docker-compose.yml` file is used when you need multiple independent containers to run together and talk to each other on a private network. For example, spinning up a Node.js API container alongside a separate PostgreSQL database container and a Redis cache container.

The Production Reality

Docker Compose is incredible for local development. However, running `docker-compose up` on a single production VPS is notoriously fragile. If the server restarts, databases get corrupted. Managing backups is difficult.

Instead, modern developers split their architecture in production:

1. Host the Database on a managed service (Atlas, Supabase).
2. Take the frontend/backend application `Dockerfile` and deploy it to a PaaS (like Remoud) that manages the scaling, SSL, and zero-downtime updates automatically.