Simple Metabase BI Docker-Compose with postgres as backend-DB and mysql as additional DB to store BI-Data

docker-compose.yml

version: "3"

services:
  metabase-app:
    image: metabase/metabase
    container_name: metabase
    restart: always
    depends_on:
     - db-backend
     - db-mysql
    environment:
     MB_DB_TYPE: postgres
     MB_DB_DBNAME: <<METABASE_DB_NAME>>
     MB_DB_PORT: 5432
     MB_DB_USER: <<METABASE_DB_USER>>
     MB_DB_PASS: <<METABASE_DB_PASS>>
     MB_DB_HOST: db-backend
     VIRTUAL_HOST: <<metabase.mydomain.com>>
     LETSENCRYPT_HOST: <<metabase.mydomain.com>>
     LETSENCRYPT_EMAIL: <<[email protected]>>
     VIRTUAL_PORT: 3000

  db-backend:
    image: postgres
    container_name: postgres_metabase_backend
    restart: always
    environment:
     POSTGRES_PASSWORD: <<METABASE_DB_PASS>>
     POSTGRES_USER: <<METABASE_DB_USER>>
     POSTGRES_DB: <<METABASE_DB_NAME>>
    volumes:
      - ./volumes/db-data:/var/lib/postgresql/data

  db-mysql:
    image: mysql/mysql-server
    container_name: mysql_database
    restart: always
    command: --default-authentication-plugin=mysql_native_password
    environment:
     MYSQL_ROOT_PASSWORD: <<MYSQL_ROOT_PASSWORD>>
     MYSQL_DATABASE: <<MYSQL_DATABASE>>
     MYSQL_USER: <<MYSQL_USER>>
     MYSQL_PASSWORD: <<MYSQL_PASS>>
    volumes:
      - ./volumes/db-mysql:/var/lib/mysql

  jwildernginxproxy:
    image: jwilder/nginx-proxy
    container_name: jwildernginxproxy
    labels:
      com.github.jrcs.letsencrypt_nginx_proxy_companion.nginx_proxy: "true"
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./volumes/certs:/etc/nginx/certs:ro
      - ./volumes/vhostd:/etc/nginx/vhost.d
      - ./volumes/html:/usr/share/nginx/html
      - /var/run/docker.sock:/tmp/docker.sock:ro
    restart: always

  letsencrypt-nginx-proxy-companion:
    image: jrcs/letsencrypt-nginx-proxy-companion
    container_name: letsencrypt-nginx-proxy-companion
    environment:
      - NGINX_PROXY_CONTAINER=jwildernginxproxy
    volumes:
      - ./volumes/certs:/etc/nginx/certs
      - ./volumes/vhostd:/etc/nginx/vhost.d
      - ./volumes/html:/usr/share/nginx/html
      - /var/run/docker.sock:/var/run/docker.sock:ro
    restart: always