Docker Concepts

What is Docker?

• Platform for building, shipping, and running applications inside containers.
• A container = lightweight runtime environment (like a mini VM but shares the host kernel).

Core Components

• Image: Blueprint for containers (read-only).
• Container: Running instance of an image.
• Dockerfile: Instructions to build an image.
• Registry: Repository to store and share images (Docker Hub, GHCR, private registry).
• Volumes: Persistent storage for containers.
• Networks: Allow containers to communicate.

Mental Model

Dockerfile → Build Image → Run Container → Attach Volume/Network → Manage Lifecycle.