containerizing-applications

Containerize applications by creating a Dockerfile with multi-stage builds to reduce image size and improve security. Define base layers, install dependencies, copy source code, and set an entrypoint. This approach works for FastAPI/Python and Next.js, producing portable images ready for deployment.

Docker Compose orchestrates multi-service applications through a docker-compose configuration file that defines services, networks, and volumes. Compose handles service wiring, health checks, and environment-specific settings, enabling local development and staging deployments without manual orchestration.

Package containerized applications for Kubernetes using Helm charts, which template deployments with environment-specific configuration, security policies, and service discovery. Helm provides production-grade packaging with compliance considerations and correct service wiring for cluster deployment.

Containerization introduces 15+ gotchas including improper image layering, missing health checks, hardcoded credentials, and incorrect network topology. This Skill documents battle-tested anti-patterns and best practices to reduce CVEs, improve security, and ensure deployment reliability across environments.

Docker Compose and Helm serve different stages: Compose handles local multi-service development, while Helm packages production Kubernetes deployments. Both follow containerization patterns for environment wiring and health checks, enabling consistent patterns from development through production.

Containerized applications handle environment-specific configuration through Docker ENV directives, docker-compose environment sections, and Helm ConfigMaps. This enables the same image to run across development, staging, and production with proper auth, CORS, and network topology wiring per environment.