Docker Architecture Overview: Components and Modules

Docker adopts a client‑server (C/S) architecture where the Docker client communicates with the Docker daemon to send container management requests.

The Docker daemon (Docker Server) acts as the core component, accepting requests, routing them via a gorilla/mux router, and invoking appropriate handlers to process each job.

Docker Engine executes internal jobs, each representing a specific operation such as creating containers, pulling images, or serving API requests.

When a job requires an image, Docker pulls it from a Docker Registry and stores it using the Graphdriver; the Registry serves as a centralized image repository.

Networkdriver configures container networking, creating bridges, virtual interfaces, IP addresses, port mappings, and firewall rules.

Execdriver (defaulting to the native driver) handles container execution, setting up namespaces, cgroups, and resource limits.

Libcontainer, a Go library, provides low‑level APIs for namespace, cgroup, AppArmor, and network management, allowing Docker to manipulate containers without external dependencies.

The Graph database, built on SQLite, records relationships between downloaded images and stores metadata such as size and root filesystem.

Finally, Docker containers represent the delivered service, encapsulating a root filesystem, allocated resources, network configuration, and the command to run.

Illustrative diagrams of the overall Docker architecture, client‑daemon interaction, server components, graph storage, drivers, and container layout are included throughout the article.