Hello @mptek, I explained nature of non-persistent and persistent images/instances in my prev posts. I already discuss this problem with few my customers. It all depends on usage of opennebula.
If you use it in “cloud” way, them it is like amazon ec2 instances (vm instances), ami images (non-persistent images) and ebs volumes (persistent images). So customer deploys new instances based on ami image (non-persistent image) and configure everything “infrastructure as code” using tools like ansible. That programatic configuration also includes attaching and mounting ebs volume (persistent image) which can be backuped. So in case of crash, they can easily deploys and configure everything by running “program”. Important data will be on ebs volumes, so preserved.
On the other hand, many people use openenbula as “vps” like hosting and deploys non-persistent instances/images. In this case there are two possible solutions (in my subjective opinion).
First one is to make every customer VPS persistent, so clone base image and make it persistent, clone base VM template, map it to that image, configure persistent IP, etc… and deploy vm.
Second one is deploying non persistent instances and do backups of that “non-persistent” images created on background.
Personally I use first approach.