This [*] is what appears in nova-scheduler after having enabled the debug.
We performed a "yum update" so, yes, we also updated libvirt (now we are running v. 4.5.0)
Thanks, Massimo
[*]
2019-07-23 16:44:34.849 12561 DEBUG nova.scheduler.filters.image_props_filter [req-52638278-51b7-4768-836a-f70d8a8b016a ab573ba3ea014b778193b6922ffffe6d ee1865a76440481cbcff08544c7d580a - default default] Instance contains properties ImageMetaProps(hw_architecture=<?>,hw_auto_disk_config=<?>,hw_boot_menu=<?>,hw_cdrom_bus=<?>,hw_cpu_cores=<?>,hw_cpu_max_cores=<?>,hw_cpu_max_sockets=<?>,hw_cpu_max_threads=<?>,hw_cpu_policy=<?>,hw_cpu_realtime_mask=<?>,hw_cpu_sockets=<?>,hw_cpu_thread_policy=<?>,hw_cpu_threads=<?>,hw_device_id=<?>,hw_disk_bus=<?>,hw_disk_type=<?>,hw_firmware_type=<?>,hw_floppy_bus=<?>,hw_ipxe_boot=<?>,hw_machine_type=<?>,hw_mem_page_size=<?>,hw_numa_cpus=<?>,hw_numa_mem=<?>,hw_numa_nodes=<?>,hw_pointer_model=<?>,hw_qemu_guest_agent=<?>,hw_rescue_bus=<?>,hw_rescue_device=<?>,hw_rng_model=<?>,hw_scsi_model=<?>,hw_serial_port_count=<?>,hw_video_model=<?>,hw_video_ram=<?>,hw_vif_model=<?>,hw_vif_multiqueue_enabled=<?>,hw_vm_mode=<?>,hw_watchdog_action=<?>,img_bdm_v2=<?>,img_bittorrent=<?>,img_block_device_mapping=<?>,img_cache_in_nova=<?>,img_compression_level=<?>,img_config_drive=<?>,img_hide_hypervisor_id=<?>,img_hv_requested_version=<?>,img_hv_type='qemu',img_linked_clone=<?>,img_mappings=<?>,img_owner_id=<?>,img_root_device_name=<?>,img_signature=<?>,img_signature_certificate_uuid=<?>,img_signature_hash_method=<?>,img_signature_key_type=<?>,img_use_agent=<?>,img_version=<?>,os_admin_user=<?>,os_command_line=<?>,os_distro=<?>,os_require_quiesce=<?>,os_secure_boot=<?>,os_skip_agent_inject_files_at_boot=<?>,os_skip_agent_inject_ssh=<?>,os_type=<?>,traits_required=<?>) that are not provided by the compute node supported_instances [[u'i686', u'kvm', u'hvm'], [u'x86_64', u'kvm', u'hvm']] or hypervisor version 2012000 do not match _instance_supported /usr/lib/python2.7/site-packages/nova/scheduler/filters/image_props_filter.py:103
2019-07-23 16:44:34.852 12561 DEBUG nova.scheduler.filters.image_props_filter [req-52638278-51b7-4768-836a-f70d8a8b016a ab573ba3ea014b778193b6922ffffe6d ee1865a76440481cbcff08544c7d580a - default default] Instance contains properties ImageMetaProps(hw_architecture=<?>,hw_auto_disk_config=<?>,hw_boot_menu=<?>,hw_cdrom_bus=<?>,hw_cpu_cores=<?>,hw_cpu_max_cores=<?>,hw_cpu_max_sockets=<?>,hw_cpu_max_threads=<?>,hw_cpu_policy=<?>,hw_cpu_realtime_mask=<?>,hw_cpu_sockets=<?>,hw_cpu_thread_policy=<?>,hw_cpu_threads=<?>,hw_device_id=<?>,hw_disk_bus=<?>,hw_disk_type=<?>,hw_firmware_type=<?>,hw_floppy_bus=<?>,hw_ipxe_boot=<?>,hw_machine_type=<?>,hw_mem_page_size=<?>,hw_numa_cpus=<?>,hw_numa_mem=<?>,hw_numa_nodes=<?>,hw_pointer_model=<?>,hw_qemu_guest_agent=<?>,hw_rescue_bus=<?>,hw_rescue_device=<?>,hw_rng_model=<?>,hw_scsi_model=<?>,hw_serial_port_count=<?>,hw_video_model=<?>,hw_video_ram=<?>,hw_vif_model=<?>,hw_vif_multiqueue_enabled=<?>,hw_vm_mode=<?>,hw_watchdog_action=<?>,img_bdm_v2=<?>,img_bittorrent=<?>,img_block_device_mapping=<?>,img_cache_in_nova=<?>,img_compression_level=<?>,img_config_drive=<?>,img_hide_hypervisor_id=<?>,img_hv_requested_version=<?>,img_hv_type='qemu',img_linked_clone=<?>,img_mappings=<?>,img_owner_id=<?>,img_root_device_name=<?>,img_signature=<?>,img_signature_certificate_uuid=<?>,img_signature_hash_method=<?>,img_signature_key_type=<?>,img_use_agent=<?>,img_version=<?>,os_admin_user=<?>,os_command_line=<?>,os_distro=<?>,os_require_quiesce=<?>,os_secure_boot=<?>,os_skip_agent_inject_files_at_boot=<?>,os_skip_agent_inject_ssh=<?>,os_type=<?>,traits_required=<?>) that are not provided by the compute node supported_instances [[u'i686', u'kvm', u'hvm'], [u'x86_64', u'kvm', u'hvm']] or hypervisor version 2012000 do not match _instance_supported /usr/lib/python2.7/site-packages/nova/scheduler/filters/image_props_filter.py:103