What is Docker, Docker Image, Docker Compose?

Docker is a platform for building, shipping, and running applications in isolated containers. Containers allow you to package an application with all its dependencies, ensuring consistent operation on any system.

Docker Image is a template or a 'snapshot' of a container, containing all the necessary files, libraries, and configurations to run an application. A container is created from an image.

Docker Compose is a tool for defining and running multi-container Docker applications. Using a docker-compose.yml file, you can describe multiple services, their relationships, networks, and volumes, and then start everything with a single command.

Example docker-compose.yml:

version: '3'
services:
  web:
    image: nginx
    ports:
      - "80:80"
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: example