# Docker Compose — Define and Run Multi-Container Applications

> Docker Compose lets you define multi-container application stacks in a single YAML file and manage their full lifecycle with simple CLI commands.

## Install

Save as a script file and run:

# Docker Compose — Define and Run Multi-Container Applications

## Quick Use
```bash
# Install (included with Docker Desktop, or standalone)
sudo apt-get install docker-compose-plugin
# Start services defined in docker-compose.yml
docker compose up -d
# Stop and remove containers
docker compose down
```

## Introduction
Docker Compose simplifies multi-container application development by letting you define services, networks, and volumes in a single `docker-compose.yml` file. It bridges the gap between writing Dockerfiles for individual containers and orchestrating them as a cohesive application stack.

## What Docker Compose Does
- Defines multi-container applications in a declarative YAML format
- Manages container lifecycle (build, start, stop, restart, destroy) with single commands
- Creates isolated networking between services automatically
- Supports volume management for persistent data across restarts
- Enables environment-specific overrides via multiple Compose files

## Architecture Overview
Docker Compose V2 is a Go-based CLI plugin for the Docker CLI, replacing the original Python implementation. It reads `docker-compose.yml` files, translates service definitions into Docker API calls, and coordinates container creation with proper dependency ordering. Compose communicates directly with the Docker Engine API and manages a project namespace that groups related resources.

## Self-Hosting & Configuration
- Included in Docker Desktop for macOS and Windows; install the `docker-compose-plugin` package on Linux
- Configuration lives in `docker-compose.yml` (and optional override files like `docker-compose.override.yml`)
- Use `.env` files for variable substitution in Compose files
- Supports build-time arguments, health checks, resource limits, and restart policies
- Profiles allow selective service activation for different workflows (e.g., debug, test)

## Key Features
- Watch mode (`docker compose watch`) for automatic rebuilds during development
- Built-in support for GPU resources and platform-specific images
- Compose Build integrates with BuildKit for efficient multi-stage and cached builds
- Service dependency management with `depends_on` and health check conditions
- Native integration with Docker Swarm for single-node production deployments

## Comparison with Similar Tools
- **Kubernetes** — full orchestration for distributed clusters; Compose targets single-host or development use
- **Podman Compose** — drop-in alternative using Podman instead of Docker Engine
- **Docker Swarm** — built-in Docker clustering; Compose files can deploy to Swarm with `docker stack deploy`
- **Dockge** — web UI wrapper around Compose for visual management
- **Kompose** — converts Compose files to Kubernetes manifests for migration

## FAQ
**Q: Is Docker Compose V2 backward-compatible with V1?**
A: Mostly yes. V2 supports the same file format but uses `docker compose` (space) instead of `docker-compose` (hyphen). A few edge-case behaviors differ.

**Q: Can I use Compose in production?**
A: Compose works well for single-server deployments. For multi-node production, consider Kubernetes or Docker Swarm.

**Q: How do I manage secrets in Compose?**
A: Use the `secrets` top-level element to reference files or environment variables, avoiding hardcoded values in the YAML.

**Q: Does Compose support GPU passthrough?**
A: Yes. Use the `deploy.resources.reservations.devices` section to specify GPU access per service.

## Sources
- https://github.com/docker/compose
- https://docs.docker.com/compose/

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Source: https://tokrepo.com/en/workflows/asset-07825c60
Author: Script Depot