What are Docker, Docker Image, and 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 a consistent environment across different machines.

Docker Image is a template or snapshot from which a container is created. It contains all the necessary files, libraries, and configurations to run the application. Images can be created based on a Dockerfile and stored in registries.

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, volumes, and networks, and then start them with a single command.

Example docker-compose.yml:

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

This will set up a web server and a database together, configuring their interaction.