packer + ansible + cloud-init; then libvirtd or proxmox or incus as you do
i also hear you can build such images straight up with nix though i have yet to try that
this post was submitted on 28 Feb 2026
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My recommendation is to use an abstraction layer that runs qemu-kvm under the hood and automate that. Some people have mentioned libvirt, but Incus is another good option.
It sounds like you want to create a vm template image.
Some options:
Both virsh and virt-manager have tools for managing libvirt xml files that you can turn into a template to use for launching additional images.
Proxmox and ovirt both have template concepts and APIs you can interact with for automation.
If you're looking to create a golden image or just automate configuration, virt-clone, ansible, puppet, packer, and even pxe boot are good options depending on the methods you prefer.
There are so many well-established ways to approach this problem domain. Just don't get decision paralysis. There isn't a best either.
Have you used ovirt? It's currently being maintained by Oracle after Red Hat gave it up.
I've been meaning to try it, but the documentation is dense and hard to get through, and I unironically find the openstack install instructions more approachable in some ways...
It has been 7 or 8 years since I touched it, but yes. I extended some intern-built VMware automation to ovirt so we could validate KVM images and reduce VMware costs for internal dev and because that was the platform the manager decided on. We initially only dedicated 6U or 8U to it.
In general, I'd say it worked just fine and the python sdk was approachable. It wouldn't be my first choice knowing it's Oracle Virtualization now, but that's a moral stance instead of technical.
As for maintaining it long term, I can't really say. I left that team to go play in the clouds with terraform and kubernetes. But I also haven't heard anything negative from that team since (and I'm still friends with one of the system engineers who is responsible for it). And there was a much needed fundamental rewrite of the bits I original extended that continued with ovirt that went smoothly.
I use this, I will say, the latest version is vibecoded with AI and it shows. I'm sticking to the previous v0.8.x release, and forking from there.
Other than that, its a great project, and works well for my needs
Good to know!
Are you looking at reproducibility for dev environments, or for a home server?
For the former, Vagrant is probably the tool you're looking for.
For the latter it depends on the level of complexity and reproducibility that you're comfortable dealing with. Something like Proxmox lets you snapshot and restore VMs, which may be enough. On the other end of the spectrum you would have golden images that you rebuild on demand, or cloud init coupled with ansible or chef to customize VMs on demand based on metadata.