Docker Deploy

Docker Deploy Skill

Deploy and manage containerized services with Docker and Docker Compose.

Deploy / Update a Service

# Pull latest image and recreate changed containers only
docker compose pull && docker compose up -d

# Force recreate a single service
docker compose up -d --force-recreate --no-deps api

# Zero-downtime rolling update (requires a load balancer)
docker compose up -d --scale api=2 --no-recreate
docker compose up -d --scale api=1

Check Status

# All services
docker compose ps

# Live logs (follow)
docker compose logs -f --tail=100 api

# Resource usage
docker stats --no-stream

# Inspect a container
docker inspect $(docker compose ps -q api)

Common Operations

# Run a one-off command in a running service
docker compose exec api bash
docker compose exec db psql -U postgres mydb

# Run migrations (one-off container)
docker compose run --rm api python manage.py migrate

# Copy a file out of a container
docker cp $(docker compose ps -q api):/app/logs/error.log ./error.log

# Hard restart (stop → rm → start)
docker compose down && docker compose up -d

Cleanup

# Remove stopped containers and unused images (safe)
docker system prune -f

# Also remove unused volumes (⚠️ check first)
docker volume ls
docker system prune -f --volumes

# Remove a specific image
docker rmi myapp:old-tag

Deployment Workflow (Production)

# 1. Pull code changes on server
git pull origin main

# 2. Build new image (if building locally)
docker compose build --no-cache api

# 3. Apply without downtime
docker compose up -d --no-deps api

# 4. Verify it started
docker compose ps api
docker compose logs --tail=50 api

# 5. Rollback if bad
docker compose up -d --no-deps api --image myapp:previous-tag

Tips

• Always use --no-deps when restarting a single service — avoids restarting dependencies
• docker compose pull before up -d ensures you get the latest image tag
• Health checks in docker-compose.yml prevent traffic before the app is ready
• Keep .env on the server — never deploy it with rsync/git (it contains secrets)