Circling back on this, I see the same in my kolla-ansible + Ussuri.
{"uuid": "a916a95d-3f9b-4e5e-9f64-894470742d8b", "hostname": "test-laurent.novalocal", "name": "test-laurent", "launch_index": 0, "availability_zone": "nova", "random_seed": "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", "project_id": "4db7dbf9961c4fc6a4589a5cb2ae3c9a", "devices": []}#
Nothing in Devices
But I see it in the network endpoint
# curl
http://169.254.169.254/openstack/2018-08-27/network_data.json{"links": [{"id": "tap1b4490ec-76", "vif_id": "1b4490ec-76b9-4223-9a31-837d60b13cc2", "type": "ovs", "mtu": 1450, "ethernet_mac_address": "fa:16:3e:58:a4:4a"}], "networks": [{"id": "network0", "type": "ipv4_dhcp", "link": "tap1b4490ec-76", "network_id": "bef77274-defd-463c-814a-5051ea2acae0"}], "services": []}#
I'll look at the code, but I am not clear where that snippet is being generated. It could be expected that the devices array is empty.