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Docker
Overview

Overview

Docker is a containerization platform that packages applications and their dependencies into lightweight, portable containers. It enables consistent environments from development to production, simplifies deployment, and optimizes resource utilization.

What Is Docker

Docker is an open-source platform that uses OS-level virtualization to deliver software in containers. Containers bundle application code with libraries and dependencies, ensuring the application runs reliably across different computing environments.

Key characteristics:

  • Containerization - Lightweight isolation using Linux kernel features (cgroups, namespaces)
  • Portability - Containers run consistently on any system with Docker
  • Efficiency - Shares host OS kernel, minimal overhead compared to VMs
  • Image layering - Reusable layers with copy-on-write filesystem
  • Docker Hub - Public registry with millions of pre-built images

What You’ll Learn

Through our Docker tutorials, you’ll master:

Fundamentals

  • Images: Building, tagging, pushing to registries
  • Containers: Running, stopping, inspecting, logs, exec
  • Dockerfile: Instructions for building images (FROM, RUN, COPY, CMD, ENTRYPOINT)
  • Volumes: Persistent data storage across container restarts
  • Networks: Container networking (bridge, host, overlay)

Production Patterns

  • Multi-stage builds: Optimized image sizes
  • Docker Compose: Multi-container application definition
  • Health checks: Container health monitoring
  • Resource limits: CPU, memory constraints
  • Security: User privileges, secrets management, image scanning

Advanced Features

  • Docker Swarm: Native container orchestration
  • BuildKit: Enhanced build performance and caching
  • Registry management: Private Docker registries
  • CI/CD integration: Automated image builds and deployments
  • Logging drivers: Centralized log management

Administration

  • Image optimization: Layer caching, minimal base images
  • Networking deep dive: Custom networks, DNS, service discovery
  • Storage drivers: Performance tuning for different workloads
  • Monitoring: Container metrics, resource usage
  • Troubleshooting: Debugging containers, inspecting layers

Learning Paths

By-Example Tutorial (Code-First)

Learn Docker through 85 annotated examples covering 95% of the platform - ideal for developers and DevOps engineers who prefer learning through working code rather than narrative explanations.

What you’ll get:

  • Self-contained, copy-paste-runnable examples
  • Heavy annotations showing build outputs and runtime behaviors
  • Progressive complexity: Beginner (30 examples) → Intermediate (30 examples) → Advanced (25 examples)
  • Production-ready patterns and best practices
  • Mermaid diagrams for complex concepts

Prerequisites and Getting Started

Prerequisites

  • Basic Linux/Unix command line knowledge
  • Understanding of application deployment concepts
  • Familiarity with package managers and dependencies
  • Docker installed (Docker Desktop or Docker Engine)

No prior Docker experience required - our tutorials start from fundamentals and progress to advanced containerization.

Quick Start

Get Docker running locally:

# Install Docker (Ubuntu/Debian)
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

# Install Docker Desktop (macOS/Windows)
# Download from https://www.docker.com/products/docker-desktop

# Verify installation
docker --version
docker run hello-world

# Run first container
docker run -it ubuntu:22.04 bash

Now you’re ready to follow along with our by-example tutorials.

Why Docker

When to Choose Docker

Docker excels in scenarios requiring:

  • Consistent environments - Identical development, staging, and production
  • Microservices - Isolated, independently deployable services
  • CI/CD pipelines - Fast, reliable builds and deployments
  • Resource efficiency - Run more applications on same hardware
  • Dependency isolation - No conflicts between application dependencies
  • Rapid deployment - Start containers in seconds

Docker vs Other Tools

  • vs Virtual Machines - Docker is lighter and faster; VMs provide stronger isolation
  • vs Kubernetes - Docker is container runtime; Kubernetes orchestrates containers at scale
  • vs Podman - Podman is daemonless and rootless; Docker has broader ecosystem
  • vs LXC - Docker provides higher-level abstractions; LXC is lower-level containerization

Next Steps

Start your Docker journey:

  1. Initial Setup - Install and configure Docker
  2. Quick Start - First container and common patterns
  3. Docker By-Example Overview - Understand the by-example approach
  4. Beginner Examples - Master fundamentals (Examples 1-30)
  5. Intermediate Examples - Production patterns (Examples 31-60)
  6. Advanced Examples - Expert mastery (Examples 61-85)

Community and Resources

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Initial Setup