Containerization
Containerization is a virtualization technology where applications are packaged together with all dependencies into isolated, portable units – containers. Docker is the most widely used container tool and is frequently integrated into CI/CD pipelines. Containers ensure that an application runs identically on any system – a decisive advantage for stable Deployment processes.
Why containers in web development?
Containers eliminate environment differences between development, staging and production. A Docker image contains the OS layer, runtime, libraries and application code. The same image runs identically on the developer's laptop, in the CI/CD system and on the production server. Combined with Deployment automation, this creates reproducible release processes.
Docker fundamentals: Image, Container, Registry
Dockerfile: build instructions for an image – defines the base image, dependencies, build steps and start command. Image: an immutable snapshot of an application including all dependencies. Container: a running instance of an image with its own filesystem and network. Registry: central storage for images (Docker Hub, GitHub Container Registry, private registries). Docker Compose orchestrates multiple containers for local development environments.
Container security and best practices
Use minimal base images (Alpine, Distroless). Run containers as non-root users. Use multi-stage builds for smaller production images. Never bake secrets into images – instead inject them at runtime via Environment Variables or Secret Management . Regularly scan images for vulnerabilities (Trivy, Snyk). Enable read-only filesystems where possible.
Container orchestration with Kubernetes
For production environments with multiple containers, Kubernetes is used as the orchestration platform. Kubernetes manages scaling, load balancing, rolling updates and self-healing automatically. For smaller projects, Docker Compose with a Reverse Proxy as the entry point is sufficient.
How we use it
Our standard setup defines the complete stack via Docker Compose: Angular frontend, Django backend, PostgreSQL, Redis and Celery. Each service has a multi-stage Dockerfile with an Alpine base image and non-root user. Local development and CI environments use the same image, eliminating "works on my machine" problems. Environment Variables are injected via .env files, while sensitive values are managed separately through Secret Management .