---

name: docker-database description: Configure database containers with security, persistence, and health checks

Docker Database Configuration Skill

Overview

This skill configures database containers following best practices for:

• Security (passwords, network isolation)
• Persistence (named volumes)
• Health checks
• Initialization scripts
• Backup and restore

Supported Databases

• PostgreSQL
• MySQL/MariaDB
• MongoDB
• Redis

Process

1. Consult Documentation

Read 05-databases.md for:

• Image versions
• Environment variables
• Health check configurations
• Volume paths
• Initialization patterns

2. Generate Configuration

PostgreSQL Configuration

Copyservices:
  postgres:
    image: postgres:16-alpine
    container_name: postgres
    restart: unless-stopped
    shm_size: 256mb
    environment:
      POSTGRES_USER: ${DB_USER:-appuser}
      POSTGRES_PASSWORD: ${DB_PASSWORD}
      POSTGRES_DB: ${DB_NAME:-appdb}
    volumes:
      - postgres_data:/var/lib/postgresql/data
      - ./init-scripts:/docker-entrypoint-initdb.d
    ports:
      - "127.0.0.1:5432:5432"
    networks:
      - database
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U ${DB_USER:-appuser} -d ${DB_NAME:-appdb}"]
      interval: 10s
      timeout: 5s
      retries: 5
      start_period: 30s

volumes:
  postgres_data:

networks:
  database:
    internal: true

MySQL Configuration

Copyservices:
  mysql:
    image: mysql:8.0
    container_name: mysql
    restart: unless-stopped
    environment:
      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
      MYSQL_DATABASE: ${DB_NAME}
      MYSQL_USER: ${DB_USER}
      MYSQL_PASSWORD: ${DB_PASSWORD}
    volumes:
      - mysql_data:/var/lib/mysql
      - ./init-scripts:/docker-entrypoint-initdb.d
    ports:
      - "127.0.0.1:3306:3306"
    command: >
      --default-authentication-plugin=mysql_native_password
      --character-set-server=utf8mb4
      --collation-server=utf8mb4_unicode_ci
    healthcheck:
      test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p${MYSQL_ROOT_PASSWORD}"]
      interval: 10s
      timeout: 5s
      retries: 5

volumes:
  mysql_data:

MongoDB Configuration

Copyservices:
  mongodb:
    image: mongo:7
    container_name: mongodb
    restart: unless-stopped
    environment:
      MONGO_INITDB_ROOT_USERNAME: ${MONGO_USER}
      MONGO_INITDB_ROOT_PASSWORD: ${MONGO_PASSWORD}
      MONGO_INITDB_DATABASE: ${MONGO_DB}
    volumes:
      - mongo_data:/data/db
      - mongo_config:/data/configdb
    ports:
      - "127.0.0.1:27017:27017"
    healthcheck:
      test: ["CMD", "mongosh", "--eval", "db.adminCommand('ping')"]
      interval: 10s
      timeout: 5s
      retries: 5

volumes:
  mongo_data:
  mongo_config:

Redis Configuration

Copyservices:
  redis:
    image: redis:7-alpine
    container_name: redis
    restart: unless-stopped
    command: >
      redis-server
      --appendonly yes
      --maxmemory 256mb
      --maxmemory-policy allkeys-lru
      --requirepass ${REDIS_PASSWORD}
    volumes:
      - redis_data:/data
    ports:
      - "127.0.0.1:6379:6379"
    healthcheck:
      test: ["CMD", "redis-cli", "-a", "${REDIS_PASSWORD}", "ping"]
      interval: 10s
      timeout: 5s
      retries: 5

volumes:
  redis_data:

Connection Strings

PostgreSQL

CopyDATABASE_URL=postgresql://user:password@db:5432/dbname

MySQL

CopyDATABASE_URL=mysql://user:password@db:3306/dbname

MongoDB

CopyMONGO_URI=mongodb://user:password@mongodb:27017/dbname?authSource=admin

Redis

CopyREDIS_URL=redis://:password@redis:6379

Backup Commands

Copy# PostgreSQL
docker compose exec -T db pg_dumpall -c -U appuser > backup.sql

# MySQL
docker compose exec -T db mysqldump -u root -p"$PASS" --all-databases > backup.sql

# MongoDB
docker compose exec -T db mongodump --archive --gzip > backup.gz

# Redis (if persistence enabled)
docker compose exec redis redis-cli -a "$PASS" BGSAVE

Restore Commands

Copy# PostgreSQL
docker compose exec -T db psql -U appuser -d appdb < backup.sql

# MySQL
docker compose exec -T db mysql -u root -p"$PASS" < backup.sql

# MongoDB
docker compose exec -T db mongorestore --archive --gzip < backup.gz

Best Practices

1. Always use named volumes for data persistence
2. Bind to localhost only (127.0.0.1) unless external access needed
3. Use internal networks to isolate database traffic
4. Implement health checks for dependency management
5. Store credentials in .env or Docker secrets
6. Use initialization scripts for schema setup
7. Regular backups before any risky operations