Home Assistant with DSM7

https://gist.github.com/maeneak/851e883eca7cddd7114f7eaed201ca9d has a pretty good guide in there.

Create a data directory & docker-compose file:

version: '3'

services:
    hassio:
        image: homeassistant/amd64-hassio-supervisor
        container_name: hassio_supervisor
        privileged: true
        security_opt:
            - seccomp:unconfined
            - apparmor:unconfined
        environment:
            - HOMEASSISTANT_REPOSITORY=homeassistant/qemux86-64-homeassistant
            - SUPERVISOR_SHARE=/volume1/docker/homeassistant
            - SUPERVISOR_NAME=hassio_supervisor
        volumes:
            - /volume1/docker/homeassistant:/data
            - /var/run/docker.sock:/var/run/docker.sock
            - /var/run/dbus:/var/run/dbus

Then run docker-compose up -d and you should be good to go.

Only thing missing was when facing path /volume1/docker/homeassistant/share is mounted on /volume1 but it is not a shared or slave mount

you need to run:

mount --make-shared /volume1/
systemctl daemon-reload

When uninstalling, run:

docker rm $(docker stop $(docker ps --filter name=hassio* -q))
docker rm $(docker stop $(docker ps --filter name=homeassistant -q))
docker rm $(docker stop $(docker ps --filter name=addon* -q))