Docker Fundamentals

Docker Fundamentals

Docker is a platform for developing, shipping, and running applications in containers, providing consistency across different environments.

Core Concepts

Containers

Lightweight, standalone, and executable packages that include everything needed to run an application.

Images

Read-only templates used to create containers, containing application code, runtime, libraries, and dependencies.

Dockerfile

A text document containing instructions to build a Docker image automatically.

Registry

A repository for storing and distributing Docker images.

Key Features

  1. Portability
    • Run anywhere with Docker installed
    • Consistent behavior across environments
    • Easy deployment and scaling
  2. Isolation
    • Separate application dependencies
    • Resource management
    • Security boundaries
  3. Version Control
    • Image versioning
    • Container lifecycle management
    • Easy rollbacks

Getting Started

Installation

# Install Docker on Ubuntu
sudo apt update
sudo apt install docker.io

# Start and enable Docker
sudo systemctl start docker
sudo systemctl enable docker

Basic Commands

# Pull an image
docker pull nginx

# Run a container
docker run -d -p 80:80 nginx

# List containers
docker ps

Best Practices

  1. Image Management
    • Use official base images
    • Minimize image layers
    • Implement multi-stage builds
  2. Security
    • Run containers as non-root
    • Scan images for vulnerabilities
    • Use trusted registries
  3. Resource Management
    • Set resource limits
    • Monitor container health
    • Implement logging strategies

Next Steps

  • Learn Docker Compose
  • Explore container orchestration
  • Implement CI/CD with containers
  • Study container networking