Changelog
Initial version
Skill Content
# Docker Compose
> Create docker-compose.yml for multi-service apps
You are a Docker DevOps engineer. The user wants to create a docker-compose.yml file for running multiple interconnected services locally.
## What to check first
- Run `docker --version` and `docker-compose --version` to confirm both are installed
- Verify the services you need (web app, database, cache, etc.) and their image names from Docker Hub or your registry
## Steps
1. Create a `docker-compose.yml` file in your project root with `version: '3.8'` at the top (compatible with Docker Engine 20.10+)
2. Define the `services:` section and list each service as a key (e.g., `web:`, `db:`, `redis:`)
3. For each service, specify the `image:` field or use `build:` with a Dockerfile path if building locally
4. Set `ports:` to map container ports to host ports using `"HOST:CONTAINER"` format (e.g., `"8080:3000"`)
5. Add `environment:` variables or reference a `.env` file with `env_file: .env` for sensitive data
6. Configure `networks:` and `volumes:` for inter-service communication and persistent data storage
7. Use `depends_on:` to control startup order (e.g., web service depends on db service)
8. Run `docker-compose up -d` to start all services in detached mode, then use `docker-compose logs -f` to monitor
## Code
```yaml
version: '3.8'
services:
web:
build: .
container_name: myapp_web
ports:
- "8080:3000"
environment:
- NODE_ENV=production
- DATABASE_URL=postgres://user:password@db:5432/myapp
- REDIS_URL=redis://cache:6379
depends_on:
- db
- cache
volumes:
- ./src:/app/src
networks:
- app-network
restart: unless-stopped
db:
image: postgres:15-alpine
container_name: myapp_db
environment:
- POSTGRES_USER=user
- POSTGRES_PASSWORD=password
- POSTGRES_DB=myapp
ports:
- "5432:5432"
volumes:
- db_data:/var/lib/postgresql/data
networks:
- app-network
restart: unless-stopped
healthcheck:
test: ["CMD-SHELL", "pg_isready -U user"]
interval: 10s
timeout: 5s
retries: 5
cache:
image: redis:7-alpine
container_name: myapp_cache
ports:
- "6379:6379"
volumes:
- cache_data:/data
networks:
- app-network
restart: unless-stopped
command: redis-server
```
*Note: this example was truncated in the source. See [the GitHub repo](https://github.com/Samarth0211/claude-skills-hub) for the latest full version.*
## Common Pitfalls
- Treating this skill as a one-shot solution — most workflows need iteration and verification
- Skipping the verification steps — you don't know it worked until you measure
- Applying this skill without understanding the underlying problem — read the related docs first
## When NOT to Use This Skill
- When a simpler manual approach would take less than 10 minutes
- On critical production systems without testing in staging first
- When you don't have permission or authorization to make these changes
## How to Verify It Worked
- Run the verification steps documented above
- Compare the output against your expected baseline
- Check logs for any warnings or errors — silent failures are the worst kind
## Production Considerations
- Test in staging before deploying to production
- Have a rollback plan — every change should be reversible
- Monitor the affected systems for at least 24 hours after the change
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*From [CLSkills.in](https://clskills.in/browse) — 2,300+ free Claude Code skills*