nova/placement-api-ref/source/update-inventories-request.json

{
    "inventories": {
        "MEMORY_MB": {
            "allocation_ratio": 2.0,
            "max_unit": 16,
            "step_size": 4,
            "total": 128
        },
        "VCPU": {
            "allocation_ratio": 10.0,
            "reserved": 2,
            "total": 64
        }
    },
    "resource_provider_generation": 1
}