Testing an Installation in a QEMU VM

The script dnf/scripts/vm-start.sh starts a QEMU virtual machine on the DNF installation image. The VM is bridged to the LAN: it receives its address from the zone gateway, just like a physical machine.

Prepare the administration workstation

The network bridge and qemu-bridge-helper come from the darkone.graphic.qemu module, to enable on the workstation that runs the VMs :

darkone.graphic.qemu = {
  enable = true;
  bridge.interface = "enp2s0";
  bridge.macAddress = "aa:bb:cc:dd:ee:ff";
};

The deployment loads the bridge without activating it. Reboot the workstation (or run nmcli connection up br0) to move its IP address onto the bridge.

Starting a VM

Generate the image
Fenêtre de terminal
```
just build-iso
```
Start the VM, from the project root
Fenêtre de terminal
```
# dnf/scripts/vm-start.sh <host>
dnf/scripts/vm-start.sh poste
```
On first run, the script creates the disk var/vm/poste.qcow2 (40 GB), ignored by git. An empty disk boots from the image.
Install

The VM screen displays its IP address and MAC. Then start the standard installation:
Fenêtre de terminal
```
just full-install poste nixos 10.0.0.50
```
After reboot, the VM boots from its disk.

Settings

Script environment variables:

Variable	Default	Role
`DISK_BUS`	`sata`	`sata` → `/dev/sda`, `nvme` → `/dev/nvme0n1`, depending on the host’s disko
`DISK_SIZE`	`40G`	Disk size, at creation
`MEMORY`	`4096`	Memory (MiB)
`CPUS`	`2`	Number of processors
`BRIDGE`	`br0`	Network bridge

Arguments placed after the host name are passed to QEMU.