docker-compose.replica.yml

version: '2'
services:

  postgres:
    image: postgres:alpine
    restart: unless-stopped
    environment:
      - POSTGRES_PASSWORD=moodle
      - POSTGRES_USER=moodle
      - POSTGRES_DB=moodle
    volumes:
      - postgres:/var/lib/postgresql/data

  redis:
    image: redis/redis-stack-server
    restart: unless-stopped
    volumes:
      - redis:/data

  moodle:
    image: jimsihk/alpine-moodle
    restart: unless-stopped
    deploy:
      replicas: 2
    environment:
      - LANG=en_US.UTF-8
      - LANGUAGE=en_US:en
      - SITE_URL=https://localhost
      - DB_TYPE=pgsql
      - DB_HOST=postgres
      - DB_PORT=5432
      - DB_NAME=moodle
      - DB_USER=moodle
      - DB_PASS=moodle
      - DB_PREFIX=mdl_
      - SSLPROXY=true
      - MOODLE_EMAIL=user@example.com
      - MOODLE_LANGUAGE=en
      - MOODLE_SITENAME=New-Site
      - MOODLE_USERNAME=moodleuser
      - MOODLE_PASSWORD=PLEASE_CHANGEME
      - SMTP_HOST=smtp.gmail.com
      - SMTP_PORT=587
      - SMTP_USER=your_email@gmail.com
      - SMTP_PASSWORD=your_password
      - SMTP_PROTOCOL=tls
      - MOODLE_MAIL_NOREPLY_ADDRESS=noreply@localhost
      - MOODLE_MAIL_PREFIX=[moodle]
      - AUTO_UPDATE_MOODLE=true
      # not suggest to enable auto update Moodle core code as it may 
      #   cause discrepancy between code and database, alternatively
      #   may start with 1 replica and then scale up after successfully
      #   deploy and update
      - UPDATE_MOODLE_CODE=false
      # uncomment below to define the session cache upon installation
      #   note: config.php will need to be changed when reverting this config
#      - SESSION_CACHE_TYPE=redis
#      - SESSION_CACHE_HOST=redis
#      - SESSION_CACHE_PORT=6379
#      - SESSION_CACHE_PREFIX=mdl
    volumes:
      - moodledata:/var/www/moodledata
    depends_on:
      - postgres
      - redis

  loadbalancer:
    image: nginx
    volumes:
      - ./nginx-lb.conf:/etc/nginx/nginx.conf:ro
      - ./https.crt:/etc/nginx/ssl/default.crt:ro
      - ./https.key:/etc/nginx/ssl/default.key:ro
    ports:
      - "80:80"
      - "443:443"
    depends_on:
      - moodle

volumes:
  postgres: null
  moodledata: null
  redis: null