Why can't I access the GPU?

Make sure you're using a base Docker image that has GPU capabilities and using an environment that has a GPU.

If you're building your own custom Docker image, make sure you've added the following environment variables to make sure the Valohai execution can access the GPU.

ENV NVIDIA_VISIBLE_DEVICES all
ENV NVIDIA_DRIVER_CAPABILITIES=compute,utility

You can also run nvidia-smi in your step's command to see which GPUs can be found using the Docker image you're using for your execution.