cinder/api-ref/source/v3/samples/group-create-request.json

{
    "group": {
        "name": "first_group",
        "description": "first group",
        "group_type": "29514915-5208-46ab-9ece-1cc4688ad0c1",
        "volume_types": [
            "4e9e6d23-eed0-426d-b90a-28f87a94b6fe",
            "c4daaf47-c530-4901-b28e-f5f0a359c4e6"
        ],
        "availability_zone": "az0"
    }
}