Docker Compose

Docker Compose is a tool for defining and running multi-container Docker applications using a declarative YAML file (compose.yaml or docker-compose.yml). It allows developers to specify services, networks, volumes, environment variables, and dependencies in a single file, then bring the entire application stack up or down with a single command. This is particularly valuable for local development environments that mirror production architectures.

Compose supports service dependencies with depends_on and health check-based startup ordering, ensuring databases and message brokers are ready before application services start. It manages named volumes for persistent data, custom bridge networks for service isolation, and bind mounts for development hot-reloading. Environment variables can be injected from .env files, shell environment, or inline definitions with variable substitution.

Modern Docker Compose v2 (integrated as a Docker CLI plugin) supports profiles for selectively enabling services, extends for sharing common configuration, and watch mode for automatic rebuilds during development. It also supports deploy configuration for resource constraints, replicas, and restart policies, making it useful for single-node production deployments and as a stepping stone toward orchestration platforms.