skill-based roadmap · DevOps
Docker Roadmap
A structured path to mastering Docker containerization, from core concepts to production-grade deployment and orchestration skills employers expect.
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1. Stage 1: Foundations & Core Concepts
What is Docker & Why Containers?
Understand the problem Docker solves before writing commands.
Installing Docker & Docker Desktop
Get a working local environment to practice every concept hands-on.
Images vs Containers vs Registries
These three terms are the mental model for everything in Docker.
Essential CLI Commands
Run, stop, inspect, and remove containers confidently from day one.
2. Stage 2: Building Images with Dockerfiles
Dockerfile Syntax & Instructions
Writing Dockerfiles is the core skill for packaging any application.
Layered Filesystem & Build Cache
Layer awareness slashes build times and image sizes dramatically.
Multi-Stage Builds
Produce lean production images by separating build and runtime stages.
Image Tagging & Pushing to Docker Hub
Sharing images is essential for team workflows and CI/CD pipelines.
3. Stage 3: Networking, Volumes & Data Persistence
Docker Networking Modes
Containers must communicate securely; networking controls how.
Volumes vs Bind Mounts
Data persistence is critical so containers can lose state safely.
Environment Variables & Secrets
Config and credentials must never be baked into images.
4. Stage 4: Docker Compose & Multi-Container Apps
Docker Compose Fundamentals
Compose orchestrates multi-service stacks with a single YAML file.
Service Dependencies & Health Checks
Apps must start in order; health checks prevent cascading failures.
Compose in Development vs Production
Knowing when to use Compose vs full orchestration is a key judgment call.
5. Stage 5: Security & Image Best Practices
Running Containers as Non-Root
Root containers are a major attack surface in production systems.
Scanning Images for Vulnerabilities
Ship secure images by catching CVEs before they reach production.
Minimizing Image Size & Attack Surface
Smaller images deploy faster, cost less, and expose fewer vulnerabilities.
6. Stage 6: CI/CD Integration & Registry Management
Building & Pushing Images in GitHub Actions
Automated image builds on every commit is the industry standard workflow.
Private Registries (ECR, GCR, GHCR)
Enterprise teams host private images rather than using public Docker Hub.
Docker BuildKit & Advanced Build Features
BuildKit unlocks parallel builds, secrets mounting, and cache exports.
7. Stage 7: Kubernetes Readiness & Production Orchestration
From Docker Compose to Kubernetes
Kubernetes is the production-grade standard; Docker is the on-ramp.
Container Resource Limits & Observability
Production containers must have guardrails to prevent resource exhaustion.
Logging & Monitoring Containers
You cannot fix what you cannot observe in a distributed container fleet.