Why it matters

Containers are foundational to modern infrastructure. Understanding Docker enables all container work.

Advertisement

The architecture

Image: read-only layered filesystem. Built from Dockerfile. Distributed via registries.

Container: running instance of image. Isolated process.

Docker basicsImagelayered fsContainerrunning instanceRegistrystorage + distributionLayers cache build steps; smaller layers = faster builds and pulls
Docker components.
Advertisement

How it works end to end

Dockerfile: instructions to build image. FROM, RUN, COPY, CMD.

Registry: Docker Hub, GHCR, ECR, GCR. Store and distribute images.

Runtime: containerd, runc, CRI-O. Docker uses containerd internally.

Compose: multi-container apps via docker-compose.yml. Networks and volumes.