I'm looking at using a script similar to https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/export_vm_as_ova.py to export VMs as OVA for backup purposes.  I tested it out and it seems that it does create a snapshot and allows me to export an OVA of a running VM.  I read in guides that the VM should be shutdown before exporting to OVA but I'm not sure if that info is still relevant.