Example script to start a simple Ubuntu VM from command line using libvirt

libvit-vm-init.sh

#!/usr/bin/env bash

# This script creates a and starts an Ubuntu VM

# requirements:
# - libvirt
# - vit-manager

set -eu -o pipefail

vm_name="libvirt-lan-test"
vm_hostname="$vm_name"
vm_root_pass="password"

vm_disk_dir="/mnt/data/libvirt-storage"
vm_disk_size="20G"
vm_disk_name="$vm_name"

vm_memory="2048" # in mebibytes
vm_vcpus="2"

vm_lan_bridge="br0"
vm_lan_mac="52:54:00:01:01:01"

ubuntu_codename="jammy"
ubuntu_arch="amd64"

force_download="false"

# do not modify

vm_disk_path="$vm_disk_dir/$vm_disk_name.qcow2"
vm_base_disk_remote_url="https://cloud-images.ubuntu.com/$ubuntu_codename/current/${ubuntu_codename}-server-cloudimg-${ubuntu_arch}-disk-kvm.img"
vm_base_disk_dir="$vm_disk_dir/base"
vm_base_disk_path="$vm_base_disk_dir/$ubuntu_codename.qcow2"


mkdir -p "$vm_disk_dir/base"
if [[ ! -f "$vm_base_disk_path" ]] || [[ "$force_download" == "true" ]]; then
  curl -L "$vm_base_disk_remote_url" --output "$vm_base_disk_path"
fi

cp "$vm_base_disk_path" "$vm_disk_path"

vm_netplan_file="
network:
  version: 2
  renderer: networkd
  ethernets:
    lan:
      dhcp4: true
      link-local: []
      match:
        macaddress: $vm_lan_mac
"

virt-customize \
  -a "$vm_disk_path" \
  --root-password "password:$vm_root_pass" \
  --run-command "dpkg-reconfigure -f noninteractive openssh-server" \
  --upload <(echo "$vm_netplan_file"):/etc/netplan/main.yaml

virt-install \
  --name "$vm_disk_name" \
  --disk "path=$vm_disk_path,format=qcow2" \
  --memory "$vm_memory" \
  --os-variant="ubuntu${ubuntu_codename}" \
  --vcpus "$vm_vcpus" \
  --network "bridge=$vm_lan_bridge,model=virtio,mac=$vm_lan_mac" \
  --graphics none \
  --autoconsole none \
  --import

echo "Run the following command to attach to the console of the VM:"
echo
echo "virsh console $vm_name"
echo