Coexisting with Pi-hole using Docker

Hi there - I’ve just got a Raspberry Pi 400, and am running Pi-hole. I’d like to also experiment with Nextclould, just internally at home - no need to access when I’m away from home right now.

I’m fairly new to this, but determined it would probably make sense to put Nextcloud in a container, because it may have dependencies or needs that would conflict with Pi-hole.

Through various tutorials, I pieced together this docker-compose file:

version: '2'

volumes:
  nextcloud:
  db:
  apps:
  config:
  data:

services:
  db:
    image: yobasystems/alpine-mariadb
    restart: always
    command: --transaction-isolation=READ-COMMITTED --binlog-format=ROW
    volumes:
      - db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=mypwhere
      - MYSQL_PASSWORD=mypwhere
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud

  app:
    image: arm32v7/nextcloud
    restart: always
    ports:
      - 8080:80
    links:
      - db
    volumes:
     - db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=mypwhere
      - MYSQL_PASSWORD=mypwhere
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud

  app:
    image: arm32v7/nextcloud
    restart: always
    ports:
      - 8080:80
    links:
      - db
    volumes:
      - nextcloud:/var/www/html/nc
      - apps:/var/www/html/nc/custom_apps
      - config:/var/www/html/nc/config
      - data:/var/www/html/nc/data
    environment:
      - MYSQL_PASSWORD=mypwhere
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud
      - MYSQL_HOST=db

It builds without error and everything seems fine - but I can’t the web interface doesn’t load - browser says there is no response. Any pointers or suggestions?