docker

name	docker
description	Docker and docker-compose configuration. Multi-stage builds, container orchestration, volume management, networking. Don't use for Kubernetes or cloud-native deployments.
model	sonnet
effort	medium
allowed-tools	Read, Write, Edit, Bash, Grep
paths	**/Dockerfile,**/docker-compose*.yml,**/.dockerignore

Docker Development

Dockerfile Best Practices

• Multi-stage builds (separate build and runtime)
• Minimal base images (alpine when possible)
• Non-root user inside container
• .dockerignore for node_modules, .git, etc
• Layer caching: COPY package*.json first, then npm install, then COPY code

Docker Compose

• Named volumes for persistent data
• Environment variables via .env file
• Health checks for dependencies
• Restart policies (unless-stopped)
• Network isolation between services

Common Stack

services:
  app:          # Application
  db:           # PostgreSQL/MongoDB
  redis:        # Cache/queues
  minio:        # Object storage (dev)