Docker

Docker is an open-source platform for packaging applications into containers: lightweight, isolated units that include the application and everything it needs to run, such as libraries and settings. A container runs the same way on a laptop, a test server or the cloud.

A Dockerfile describes how to build an image, and containers are running instances of an image. Containers share the host's operating system kernel, so they start in seconds and use far fewer resources than virtual machines. Docker Compose runs multi-container applications, and Kubernetes orchestrates containers at scale.

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --omit=dev
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]