Hello Lukas,
This is not recommended for production. Imagine the scenario that your physical server is down, so all your controllers will go down with it. While you will try to get the VMs running on another server, you will not manage your network (vManage), bring up more WAN edges (vBond) or even have control plane (vSmart), even thouth WAN Edges will keep working on the last state for a few hours.
Other consideration regarding have more VMs (distributed across multiple servers) is to have proper capacity for your network, Cisco SDWAN is a Scale-Out model so depending on how many WAN edges you have, you need more controllers.
I hope it helps.
Henrique
