Docker Basics

What is Docker?

Docker packages applications and dependencies into lightweight containers, ensuring consistent behavior across environments.

Installation

curl -fsSL https://get.docker.com | sh
sudo usermod -aG docker $USER
docker run hello-world

Key Commands

docker pull nginx
docker run -d --name my-nginx -p 80:80 nginx
docker ps
docker logs my-nginx
docker exec -it my-nginx bash
docker stop my-nginx && docker rm my-nginx

Docker Compose

# docker-compose.yml
services:
  web:
    image: nginx
    ports: ["80:80"]
  db:
    image: mysql:8
    environment:
      MYSQL_ROOT_PASSWORD: secret

docker compose up -d
docker compose down

Dockerfile

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --production
COPY . .
CMD ["node", "server.js"]