Two of the same MAC address can't exist in the same IP space, else the router can't route packets to them.
Yes, this seems to be my problem, both the host and the vm got the same IP, and I think I cannot send any traffic to either my host or vm. So my router is probably confused, as you suggested.
Is there an issue with using Docker for this?
I forgot to mention this, docker indeed work. However, ha requires a privileged docker running as root, which means ha essentially runs as root on the host.
This is fine on dedicated hardware, but as my server have other infrastructure on there, running ha as root can be a security risk.