Containerization Fundamentals
Containers have revolutionized how we build and deploy software. Here's everything you need to know to get started.
What is Docker?
Docker packages your application and all its dependencies into a standardized unit called a container. Think of it as a lightweight, portable virtual machine.
Why Docker? - "Works on my machine" problem solved - Consistent environments - Fast deployment - Resource efficient - Easy scaling
Docker Basics
Key Concepts: - Image: Blueprint for containers - Container: Running instance of an image - Dockerfile: Instructions to build an image - Registry: Storage for images (Docker Hub)
Essential Commands:
`bash
docker build -t myapp . # Build image
docker run -p 3000:3000 myapp # Run container
docker ps # List running containers
docker stop `
Sample Dockerfile
`dockerfile
FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
CMD ["npm", "start"]
`
What is Kubernetes?
Kubernetes (K8s) orchestrates containers at scale. It handles deployment, scaling, and management of containerized applications.
Why Kubernetes? - Automatic scaling - Self-healing - Load balancing - Rolling updates - Secret management
Kubernetes Core Concepts
- Pod: Smallest deployable unit
- Deployment: Manages pod replicas
- Service: Network endpoint for pods
- Ingress: External access to services
- ConfigMap/Secret: Configuration management
Learning Path
Week 1-2: Docker - Install Docker Desktop - Build and run containers - Write Dockerfiles - Use Docker Compose
Week 3-4: Kubernetes Basics - Use minikube locally - Deploy simple applications - Understand pods and services - Learn kubectl commands
Month 2: Intermediate - Deployments and scaling - ConfigMaps and Secrets - Persistent storage - Ingress controllers
Hands-On Projects
- Containerize a web app
- Multi-container with Docker Compose
- Deploy app to Kubernetes
- Set up auto-scaling
Conclusion
Docker and Kubernetes are essential DevOps skills. Start with Docker, master it, then move to Kubernetes for orchestration.
Check out our DevOps Engineer career roadmap!