cloud-init

https://cloudinit.readthedocs.io/en/latest/

libvirt : https://cloudinit.readthedocs.io/en/latest/howto/run_cloud_init_locally.html#libvirt

QEMU : https://cloudinit.readthedocs.io/en/latest/tutorial/qemu.html

Exemples : https://cloudinit.readthedocs.io/en/latest/reference/examples.html