fail to add nvdimm device

[yluinca]

Hello, I'm able to add a nvdimm device via vcenter GUI, and I captured the code. However, when I tried to program it (similar to the captured code) to add the nvdimm device, I got error InvalidDeviceSpec error. Any idea? Appreciate any help here.

pyVmomi.VmomiSupport.InvalidDeviceSpec: (vim.fault.InvalidDeviceSpec) {
dynamicType = ,
dynamicProperty = (vmodl.DynamicProperty) [],
msg = "Invalid configuration for device '0'.",
faultCause = ,
faultMessage = (vmodl.LocalizableMessage) [
(vmodl.LocalizableMessage) {
dynamicType = ,
dynamicProperty = (vmodl.DynamicProperty) [],
key = 'com.vmware.vim.vpxd.vmprov.invalidNVDIMMPolicy',
arg = (vmodl.KeyAnyValue) [],
message = 'com.vmware.vim.vpxd.vmprov.invalidNVDIMMPolicy'
},
(vmodl.LocalizableMessage) {
dynamicType = ,
dynamicProperty = (vmodl.DynamicProperty) [],
key = 'com.vmware.vim.vpxd.vpx.vmprov.DeviceStr',
arg = (vmodl.KeyAnyValue) [
(vmodl.KeyAnyValue) {
dynamicType = ,
dynamicProperty = (vmodl.DynamicProperty) [],
key = 'deviceStr',
value = 'New NVDIMM'
}
],
message = 'Device: New NVDIMM.'
}
],
property = '',
deviceIndex = 0
}

Captured code from vcenter for adding a 10G nvdimm device:
#---------------ReconfigVM_Task---------------
spec = vim.vm.ConfigSpec()
spec_deviceChange_0 = vim.vm.device.VirtualDeviceSpec()
spec_deviceChange_0.fileOperation = create
spec_deviceChange_0.device = vim.vm.device.VirtualNVDIMM()
spec_deviceChange_0.device.backing = vim.vm.device.VirtualNVDIMM.BackingInfo()
spec_deviceChange_0.device.backing.fileName = ''
spec_deviceChange_0.device.controllerKey = 27000
spec_deviceChange_0.device.capacityInMB = 10240
spec_deviceChange_0.device.deviceInfo = vim.Description()
spec_deviceChange_0.device.deviceInfo.summary = 'New NVDIMM'
spec_deviceChange_0.device.deviceInfo.label = 'New NVDIMM'
spec_deviceChange_0.device.key = -111
spec_deviceChange_0.operation = add
spec.deviceChange = [spec_deviceChange_0]
spec.cpuFeatureMask = []
managedObject.ReconfigVM_Task(spec) # VirtualMachine-vm-933962

Test code:
def add_nvdimm_device(si, vm_obj):
# Add NVDIMM device
nvdimm_spec = vim.vm.device.VirtualDeviceSpec()
nvdimm_spec.fileOperation = "create"
nvdimm_spec.operation = vim.vm.device.VirtualDeviceSpec.Operation.add
nvdimm_spec.device = vim.vm.device.VirtualNVDIMM()
nvdimm_spec.device.deviceInfo = vim.Description()
nvdimm_spec.device.deviceInfo.summary = "New NVDIMM"
nvdimm_spec.device.deviceInfo.label = "New NVDIMM"

nvdimm_spec.device.backing = vim.vm.device.VirtualNVDIMM.BackingInfo()
nvdimm_spec.device.backing.fileName = ""
nvdimm_spec.device.capacityInMB = 8192
nvdimm_spec.device.key = -114
nvdimm_spec.device.controllerKey = 27000

spec = vim.vm.ConfigSpec()
spec.deviceChange = [nvdimm_spec]
spec.cpuFeatureMask = []
task = vm_obj.ReconfigVM_Task(spec=spec)
tasks.wait_for_tasks(si, [task])
return True