tangledgroup Docker Platform Reference (2026-04-16)
Overview
Docker is a platform for building, shipping, and running containerized applications. It consists of several integrated components:
- Docker Engine — The core container runtime (daemon + CLI) that builds images, runs containers, manages networks and volumes
- Docker Desktop — Application for Mac, Windows, and Linux providing Docker Engine, CLI, Compose, BuildKit, Extensions, Kubernetes integration, and observability tools
- Docker Compose — Tool for defining and running multi-container applications using YAML configuration files (Compose Specification)
- Docker Buildx / BuildKit — Advanced build capabilities including multi-platform images, cache export/import, build provenance, LLB frontend, and GitHub Actions integration
- Docker Hub — Default public registry for image distribution with automated builds, webhooks, and vulnerability scanning
- Docker Contexts — Manage connections to multiple Docker Engine instances from a single client
When to Use
- Writing or debugging Dockerfiles
- Configuring multi-container applications with Docker Compose
- Setting up container networking (bridge, host, overlay, macvlan)
- Managing persistent storage with volumes and bind mounts
- Building multi-platform container images
- Deploying containers with Swarm orchestration
- Working with Docker Engine API programmatically
- Troubleshooting Docker environments
- Configuring Docker Desktop features and extensions
- Implementing container security best practices
Core Concepts
Containers are isolated, lightweight runtime instances of images. They package application code, dependencies, and configuration into a standardized unit that runs consistently across environments.
Images are read-only templates containing the filesystem layers and metadata needed to run containers. Images are built from Dockerfiles and stored in registries.
Dockerfile is a text file with instructions for building an image. Each instruction creates a layer, enabling caching and efficient rebuilds.
Compose Specification defines multi-container applications as YAML files. Services, networks, volumes, configs, and secrets are declared declaratively. Compose v2 (v1.27.0+) implements the unified specification, merging legacy 2.x and 3.x formats.
BuildKit is the modern build backend that replaces the legacy builder. It provides parallel builds, better caching, SSH/socket mounting during builds, multi-platform support, and export to various cache backends. Enabled by default in recent Docker versions.
Advanced Topics
Dockerfile Reference: Complete instruction reference including FROM, RUN, COPY, ADD, CMD, ENTRYPOINT, ENV, ARG, EXPOSE, VOLUME, USER, WORKDIR, ONBUILD, STOPSIGNAL, HEALTHCHECK, SHELL, parser directives, BuildKit mount syntax, and here-documents → Dockerfile Reference
Compose File Reference: Services attributes (image, build, command, depends_on, ports, volumes, environment, networks, deploy, healthcheck, secrets, configs), top-level elements (networks, volumes, configs, secrets, profiles, include, extend), interpolation, merge rules → Compose File Reference
Docker Compose CLI: Commands for managing multi-container applications including up/down/build/logs/exec/ps/pull/push/run/start/stop/restart/fkill/kill/events/top/wait/version, with profiles, project names, and environment file support → Docker Compose CLI
Docker Engine & CLI Reference: Core Docker commands (container, image, volume, network, buildx, compose, context, system, swarm), daemon configuration, storage drivers, logging drivers, proxy configuration → Docker Engine and CLI
Networking & Storage: Network drivers (bridge, host, overlay, macvlan, ipvlan, none), port publishing, iptables/nftables integration, volumes vs bind mounts vs tmpfs, storage drivers (overlay2, btrfs, zfs, vfs) → Networking and Storage
BuildKit & Buildx: Multi-platform builds, cache backends (registry, local, gha, s3), build provenance and attestations, GitHub Actions integration, LLB frontend, build checks, export targets → BuildKit and Buildx
Swarm & Orchestration: Swarm mode for container orchestration with service discovery, load balancing, rolling updates, secrets management, and distributed logging → Swarm Orchestration
Docker APIs: Engine API (RESTful, versions v1.24–v1.54), Docker Hub API, Registry API (OCI Distribution spec), Extensions SDK for Docker Desktop plugins → Docker APIs