Docker packages an application and its runtime requirements into an image that can run as a container. This helps teams reduce “works on my machine” differences, but Docker is not a magic security boundary or a replacement for understanding the application.
Start with a small Python service. Write a Dockerfile, install dependencies in a build layer, copy the application, and define the startup command. Run the container with an explicit port mapping and environment configuration. Use volumes when data must survive container replacement, and use a compose file when several services need to work together.
Production images should be small, updated, non-root where practical, and scanned for vulnerabilities. Secrets should not be baked into image layers. Add health checks, logs, resource limits, and a rollback plan. Docker is easiest to learn when each command is connected to a visible application behavior.