some hints which helped me:

docker-compose.yml, some ports

version: '2'

services:
iobroker:
restart: always
image: buanet/iobroker:latest
container_name: iobroker
hostname: iobroker
ports:
- "8081:8081"
- "1880:1880" #node-red
- "1883:1883" #mqtt
- "2001:2001" #homematic
- "2010:2010" #homematic
- "8082:8082" #iobroker admin
- "8282:8282" #flot
- "8088:8088" #terminal
- "8284:8284" #socketIO
- "33980:33980" #Alexa
- "37325:37325" #Alexa
volumes:
- ./iobrokerdata:/opt/iobroker

Adapter alexa 2.0

Externer Container: IP docker container
Proxy-Port choose at free will and add it to the docker ports

Grafana

to use grafana with docker-compose and to share a panel in vis in ioBroker I used this in docker-compose.yml:

grafana:
image: grafana/grafana:latest
container_name: grafana
restart: unless-stopped
ports:
- "3000:3000"
- "3306:3306"
volumes:
- ./grafanadata:/grafana
- /var/lib/grafana:/var/lib/grafana
environment:
- GF_AUTH_ANONYMOUS_ENABLED=true
- GF_SECURITY_ALLOW_EMBEDDING=true