Houdini to Arnold GPU

I have htoa-5.2.1_r17b38c9_houdini-18.0.416 installed on my Ubuntu 18.04 server running Deadline and Houdini 18.0.416 with NVIDIA driver 440.82.

I can render from the GPU interactively in Houdini, as well as when I do hython and run hou.node("/out/arnold1").render() however rendering with hrender_dl.py does not seem to be able to run the gpu for some reason.

I’ve tried adding the following lines to hrender_dl.py to try and manually make sure it’s using the same parameters as the Houdini ROP. Still not picking up the GPU device.
if gpus is not None:
gpu_string = " ".join(list("gpu%s" % gpu for gpu in gpus.split(",")))

00:00:00 456MB WARNING | options.render_device: enumerated value -1 is out of range
00:00:00 456MB WARNING | options: could not set INT parameter “render_device”