network     0.1.1b2
vm          0.1.1b3

 az vmss create \
--public-ip-address-dns-name '' \
--image /subscriptions/XXXXX/resourceGroups/XXXXX/providers/Microsoft.Compute/images/XXXXX-image.Feb.13.2017 \
--os-type linux \
--admin-username XXXXX \
--ssh-key-value ~/.ssh/XXXX\
--resource-group XXXXX \
--location southcentralus \
--name 2.23.2017-XXXXX \
--public-ip-address '' \
--subnet '/subscriptions/XXXXX/resourceGroups/XXXXX/providers/Microsoft.Network/virtualNetworks/XXXXX/subnets/XXXXX' \
--load-balancer ''

At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/arm-debug for usage details. {
  "error": {
    "details": [
      {
        "code": "InvalidJsonReferenceFormat",
        "message": "Reference Id /subscriptions/XXXXX/resourceGroups/XXXXX/providers/Microsoft.Network/virtualNetworks/None/subnets//subscriptions/XXXXX/resourceGroups/XXXXX/providers/Microsoft.Network/virtualNetworks/XXXXX/subnets/XXXXX is not formatted correctly. The Id is expected to reference resources of type virtualNetworks/subnets. Path Properties.UpdateGroups[0].NetworkProfile.networkInterfaceConfigurations[0].properties.ipConfigurations[0].properties.subnet."
      }
    ],
    "code": "InvalidRequestFormat",
    "message": "Cannot parse the request."
  }
}  Correlation ID: XXXXX