nova/doc/notification_samples/aggregate-create-start.json

{
    "priority": "INFO",
    "payload": {
        "$ref": "common_payloads/AggregatePayload.json#",
        "nova_object.data": {
            "hosts": null,
            "id": null
        }
    },
    "event_type": "aggregate.create.start",
    "publisher_id": "nova-api:fake-mini"
}