Containerization

Containerization

A container packages an application with its dependencies, so "it works on my machine" stops being an excuse. A basic Dockerfile (FROM, COPY, RUN, CMD, EXPOSE, WORKDIR), the main CLI commands, port mapping, and a simple docker-compose.yml for an app-plus-database setup are enough to guarantee consistency across environments, without needing orchestration such as Kubernetes.

Starting Points

• Docker. Get Started.
• KodeKloud (2018). Docker for the Absolute Beginner - Hands-On. Packt.
• Nickoloff, J., & Kuenzli, S. (2019). Docker in Action (2nd ed.). Manning.
• Poulton, N. (2025). Docker Deep Dive (5th ed.). Packt.

Key Points

• You write a basic Dockerfile that correctly builds an image for a simple application.
• You build and run a container from a Dockerfile.
• You explain why containerization is useful (consistency across environments, isolation).
• You use basic Docker commands (build, run, ps, stop, logs) to manage containers.
• You write a basic docker-compose.yml to run multiple containers together (e.g. app + database).
• You explain why Docker Compose is useful compared to running containers individually.