Install on KVM and libvirt

Start gate42 with virt-install, or with plain QEMU.

With libvirt (virt-install)

A LAN network without DHCP, since gate42 serves the LAN's DHCP itself:

cat > gate42-lan.xml <<'EOF'
<network>
  <name>gate42-lan</name>
  <bridge name="virbr42"/>
</network>
EOF
sudo virsh net-define gate42-lan.xml
sudo virsh net-start gate42-lan
sudo virsh net-autostart gate42-lan

The disk and the VM. The default network is the WAN (NAT to the internet):

sudo cp gate42-1.8.2-b17-amd64.qcow2 /var/lib/libvirt/images/gate42.qcow2
sudo qemu-img resize /var/lib/libvirt/images/gate42.qcow2 20G
sudo virt-install --name gate42 --memory 4096 --vcpus 2 --import \
  --osinfo freebsd13.1 \
  --disk /var/lib/libvirt/images/gate42.qcow2,bus=virtio \
  --network network=default,model=virtio \
  --network network=gate42-lan,model=virtio \
  --graphics vnc --noautoconsole
sudo virsh console gate42

The serial console shows the root password after one to two minutes (first boot). Leave it with Ctrl+]. Other VMs on gate42-lan get their address from gate42.

With plain QEMU

For a quick look on a Linux machine with KVM:

qemu-img create -f qcow2 -F qcow2 -b gate42-1.8.2-b17-amd64.qcow2 gate42-try.qcow2 20G
qemu-system-x86_64 -machine q35,accel=kvm -cpu host -m 4096 -smp 2 \
  -drive file=gate42-try.qcow2,if=virtio \
  -netdev user,id=wan -device virtio-net-pci,netdev=wan \
  -netdev user,id=lan,net=192.168.1.0/24,host=192.168.1.254,restrict=on,hostfwd=tcp:127.0.0.1:8443-192.168.1.1:8443 \
  -device virtio-net-pci,netdev=lan \
  -nographic

The serial console is in the terminal. Log in to the GUI at https://127.0.0.1:8443. The first command keeps the downloaded image unchanged: all changes go to gate42-try.qcow2.