Overview
This template ships a clean nixos-25.11 image, ready to reference from any vm block. vmlab keeps one copy of the backing file on the host and boots each guest as a qcow2 linked clone, so a lab of ten machines costs little more than one base image on disk.
Reference it in a lab
vmlab.wcl
import <vmlab.wcl>
lab "demo" {
segment "lan" {
subnet = "10.99.0.0/24"
nat = true
}
vm "guest" {
template = "x86_64/nixos-25.11"
nic { segment = "lan" }
}
}
Boot it
shell
$ vmlab up
✔ pulled x86_64/nixos-25.11 (20 GiB)
✔ guest · 1 segment up