Hi,
I have made a lot of research about this, and found a few threads; but I could not find a solution. Actually I am a newbie and probably I don’t know the exact English technical terms to make a comprehensive research. So, if the things that I am going to ask are obvious things, I am sorry.
I am trying to use Raspberry Pi 4 4gb for automation of six different RV’s (one for each). I am using Home Assistant for this. I also want to use Volumio for music in the same Raspberry.
Eventually, if I succeed to do this, I want to create two instances of volumio and create two zones with one raspberry (by using some cheap DACs).
Avoiding ground loop between amplifier and Raspberry was a problem for me and I solved it. My electronic knowledge is much better than my software skills. 
Using multiple raspberries will be much more complex elecronics wise and since I am going to use this in a RV, power consumption is also a problem. One raspberry will consume much less power, even if it uses more CPU and RAM. I tested it. Also it will be much smaller.
That is why, I want to integrate home assistant and two instances of Volumio in one raspberry.
I succeeded home assistant + two zone media player by using Logitech Media Server and two Squeezelite instances; but the visual of LMS can not be compared with Volumio. Volumio is much better.
So, is there a way to use volumio in docker? Or is there a way to create virtual machine in raspberry and install volumio?
I tried to install home assistant supervised (using docker) to debian buster version of volumio. Could not install it. That also can be a solution. One volumio instance and homeassistant would be enough for me. Has anyone accomplished something like that?
Also, usb boot would be perfect in volumio debian buster version, if it is ever possible to install Home Assistant on it. Home Assistant doesn’t like sd cards.