version: "3"
services:
  web:
    image: web:1
    depends_on:
      - db
    ports:
      - 8080:80
    environment:
      - MYSQL_HOST=db
      - MYSQL_DATABASE=docker
      - MYSQL_USER=docker
      - MYSQL_PASSWORD=docker
  db:
    image: mariadb:10.7.1
    environment:
      - MYSQL_ROOT_PASSWORD=docker
      - MYSQL_DATABASE=docker
      - MYSQL_USER=docker
      - MYSQL_PASSWORD=docker
    volumes:
      - mariadb-data:/var/lib/mysql
    deploy:
      placement:
        constraints: [node.labels.type == db]
volumes:
  mariadb-data: