Docker Getting Started

Docker is a containerization platform that makes it easy to build, package, and run applications in containers.

What is Docker?

Docker allows you to package your application and its dependencies into a standardized unit called a container. This ensures that your application runs the same way regardless of where the container is deployed.

Installation

Linux

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

macOS and Windows

Download Docker Desktop from docker.com

Your First Container

# Run a simple container
docker run hello-world

# Run an interactive container
docker run -it ubuntu /bin/bash

Docker Images

Docker images are blueprints for containers.

Building an Image

Create a Dockerfile:

FROM node:18
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
CMD ["npm", "start"]

Build the image:

docker build -t my-app:1.0 .

Docker Containers

Containers are running instances of images.

Common Commands

# List running containers
docker ps

# List all containers
docker ps -a

# Start a container
docker run -d --name myapp my-app:1.0

# Stop a container
docker stop myapp

# View logs
docker logs myapp

Docker Compose

Manage multi-container applications:

version: '3'
services:
  web:
    build: .
    ports:
      - "3000:3000"
  db:
    image: postgres:15
    environment:
      POSTGRES_PASSWORD: secret

docker-compose up

Next Steps

• Learn about Docker networks
• Explore Docker volumes
• Practice building and pushing images to registries