Docker Fundamentals: Understanding Containers and Images

Lesson 1 • Introduction to OS-Level Isolation

Explains kernel namespaces and cgroups as the Linux primitives enabling containers. Connects low-level OS features to container behaviour students will observe later.

Lesson 2 • The Container Ecosystem Overview

Maps the major tools, runtimes, and standards in the container landscape. Orients students before they interact with any specific tooling.

Lesson 3 • Traditional Virtualisation Concepts

Covers hypervisors, guest OSes, and resource overhead in VM-based environments. Grounds students in the problem space that containers solve.

Lesson 1 • Docker Daemon Configuration

Covers the daemon configuration file, logging drivers, and storage driver selection. Proper configuration prevents performance and storage issues in subsequent exercises.

Lesson 2 • Installing Docker on Major Platforms

Walks through installation on Linux, macOS, and Windows environments. Students leave with a running daemon regardless of their host OS.

Lesson 3 • Docker Architecture Deep Dive

Explains the client-daemon-registry model and how components communicate. Understanding architecture prevents misdiagnosis of errors encountered in later chapters.

Lesson 1 • Pulling and Tagging Images

Covers image naming conventions, tag semantics, and digest-based pinning. Students learn to reference images precisely to ensure reproducible environments.

Lesson 2 • Working with Private Registries

Demonstrates authentication, pushing images, and configuring registry mirrors. Students can integrate Docker into organisational workflows requiring private storage.

Lesson 3 • Managing Local Image Storage

Addresses pruning, disk usage analysis, and image export and import workflows. Students maintain a clean local environment throughout the course.

Lesson 4 • Understanding Image Layers

Explains the union filesystem, layer stacking, and copy-on-write mechanics. Layer knowledge is prerequisite for efficient Dockerfile authoring in the next chapter.

Lesson 1 • Layer Caching and Build Optimisation

Explains cache invalidation rules and instruction ordering strategies to minimise rebuild time. Optimised builds accelerate the development feedback loop.

Lesson 2 • Multi-Stage Builds

Teaches multi-stage syntax to separate build and runtime environments in one Dockerfile. Students produce significantly smaller production images without extra tooling.

Lesson 3 • Dockerfile Syntax and Structure

Introduces every core instruction and the order in which Docker processes them. A solid syntax foundation prevents the majority of build errors students encounter.

Lesson 4 • Debugging Failed Builds

Covers build output interpretation, intermediate container inspection, and BuildKit debug features. Students resolve build failures independently and efficiently.

Lesson 1 • Container Logging and Inspection

Uses docker logs, docker inspect, and stats to observe container behaviour. Students diagnose runtime issues without entering the container.

Lesson 2 • Resource Constraints and Limits

Applies CPU, memory, and I/O limits to containers using runtime flags. Students prevent noisy-neighbour problems in shared host environments.

Lesson 3 • Container Lifecycle Commands

Covers create, start, stop, restart, pause, and remove commands with their flags. Students control every lifecycle state a container can occupy.

Lesson 4 • Restart Policies and Health Checks

Configures restart policies and HEALTHCHECK instructions for self-healing containers. Students build containers that recover automatically from transient failures.

Lesson 1 • Container DNS and Service Discovery

Explains Docker's embedded DNS server and automatic name resolution on user-defined networks. Students connect containers by name instead of fragile IP addresses.

Lesson 2 • Network Troubleshooting Techniques

Applies tools like ping, curl, and netstat inside containers to diagnose connectivity issues. Students resolve network problems without leaving the Docker CLI.

Lesson 3 • Port Publishing and Exposure

Covers EXPOSE, -p, and -P flags and the iptables rules Docker manages. Students safely expose container services to host and external traffic.

Lesson 4 • Creating and Managing Networks

Demonstrates creating, connecting, disconnecting, and removing user-defined networks. Students build isolated network segments for multi-container applications.

Lesson 1 • Container Storage Fundamentals

Explains the writable container layer, its ephemerality, and why external storage is needed. Motivates every storage pattern introduced in subsequent sections.

Lesson 2 • tmpfs Mounts and In-Memory Storage

Uses tmpfs mounts for sensitive or ephemeral data that must not touch disk. Students apply tmpfs to secrets and high-speed temporary workloads.

Lesson 3 • Bind Mounts

Mounts host filesystem paths into containers for development and configuration injection. Students understand bind mount risks and appropriate use cases.

Lesson 4 • Volume Backup and Migration

Demonstrates backup, restore, and migration patterns using helper containers and archives. Students protect stateful data and move it across environments.

Lesson 1 • Running and Managing Compose Stacks

Covers up, down, start, stop, and scale commands for Compose-managed stacks. Students operate multi-service applications as a single unit.

Lesson 2 • Networking in Compose

Explains default network creation, custom networks, and inter-service DNS in Compose. Students wire services together correctly without manual network commands.

Lesson 3 • Docker Compose Concepts and Syntax

Introduces the Compose file schema, service definitions, and YAML structure. Students read and write Compose files before running any multi-container stack.

Lesson 4 • Compose Profiles and Override Files

Uses profiles and override files to manage environment-specific service sets. Students maintain a single source of truth across development, testing, and staging.