Open Stack

What are people using to perform image based backups of Windows and Linux VMs in OpenStack?  I am using KVM as the hypervisor, Ceph for block storage and Swift for object storage.  I know Cinder can backup volumes that are not in use (at least in Juno, that may have changed in Kilo).   I am looking for an image backup solution that allow the backup of online KVM VMs.  Integration with OpenStack would be nice but isn't a must.

Thanks,

Brendan Johnson