Updated: 28 September 2026 · Applies to: Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9
Cloud images (qcow2) usually have no password, so you need to add an SSH key before the first boot. virt-sysprep (or virt-customize) can do that without starting the image.
1. Install the tools
dnf install guestfs-tools # AlmaLinux / Rocky 9 apt install libguestfs-tools # Ubuntu / Debian
2. Download a cloud image
cd /var/lib/libvirt/images wget https://repo.almalinux.org/almalinux/9/cloud/x86_64/images/AlmaLinux-9-GenericCloud-latest.x86_64.qcow2 # Ubuntu 24.04: https://cloud-images.ubuntu.com/noble/current/noble-server-cloudimg-amd64.img
3. Add your key
virt-sysprep -a AlmaLinux-9-GenericCloud-latest.x86_64.qcow2 \ --ssh-inject root:file:/root/.ssh/id_ed25519.pub \ --hostname vm1 --selinux-relabel
Use --ssh-inject user:file:path for another user (the user must exist in the image). Leave out --selinux-relabel for Ubuntu and Debian images.
4. Boot it
virt-install --name vm1 --memory 2048 --vcpus 2 --import \ --disk AlmaLinux-9-GenericCloud-latest.x86_64.qcow2 --osinfo almalinux9 --graphics none
Note: Cloud images also run cloud-init at boot. If you do not provide cloud-init data, boot may pause while it looks for a data source; you can also let virt-install pass the key through cloud-init instead of virt-sysprep: --cloud-init root-ssh-key=/root/.ssh/id_ed25519.pub.
