I've seen this thread here: Network-manager where someone asked about installing network-manager in OMV and the reply was very clear: "Installing network-manager is a bad idea since OMV manages the network settings. Installing packages from sid is generally a bad idea as well."
At the moment I have set up an OMV installation in Virtualbox and set it up with Portainer and Docker, OMV Extras and a couple of attached virtual hard drives for testing and it's all working very well.
As an experiment, I wanted to see how a Home Assistant docker container would run on OMV so I set it up using the manual "supervised" installation commands.
Part of the installation is that it requires network-manager so I took a snapshot on the virtual machine as a precaution and installed network-manager using sudo apt, bearing the above warnings in mind. To my surprise, everything seems to work fine after install. I even changed the IP address of the machine using the OMV interface and there are no apparent problems.
Now I have no doubt that installing network-manager on OMV is generally a bad idea since I'm guessing it uses it's own networking system/settings but wanted to ask if anyone could explain more abot what kind of issues it would cause and specifically and if there are ways to meet the requirements of Home Assistant with network-manager installed while also keeping OMV problem free? I don't notice any issues with my test installation now, but I suspect problems could arise in future with network-manager installed?