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Hello, Satish.

I've been working with vGPU lately and I believe I can answer your
questions:

1. As you pointed out in question #2, the pci-passthrough will allocate
the entire physical GPU to one single guest VM, while vGPU allows you to
spawn from 1 to several VMs using the same physical GPU, depending on
the vGPU type you choose (check NVIDIA docs to see which vGPU types the
Tesla V100 supports and their properties);
2. Correct;
3. To use vGPU, you need vGPU drivers installed on the platform where
your deployment of OpenStack is running AND in the VMs, so there are two
drivers to be installed in order to use the feature. I believe both of
them have to be purchased from NVIDIA in order to be used, and you would
also have to deploy an NVIDIA licensing server in order to validate the
licenses of the drivers running in the VMs.
4. You can see what the instructions are for each of these scenarios in
[1] and [2].

There is also extensive documentation on vGPU at NVIDIA's website [3].

[1] https://docs.openstack.org/nova/wallaby/admin/virtual-gpu.html
[2] https://docs.openstack.org/nova/wallaby/admin/pci-passthrough.html
[3] https://docs.nvidia.com/grid/13.0/index.html

Regards,
Gustavo.

On 17/01/2022 14:41, Satish Patel wrote:
> [Please note: This e-mail is from an EXTERNAL e-mail address]
> 
> Folk,
> 
> We have Tesla V100 32G GPU and I’m trying to configure with openstack wallaby. This is first time dealing with GPU so I have couple of question.
> 
> 1. What is the difference between passthrough vs vGPU? I did google but not very clear yet.
> 2. If I configure it passthrough then does it only work with single VM ? ( I meant whole GPU will get allocate to single VM correct?
> 3. Also some document saying Tesla v100 support vGPU but some folks saying you need license. I have no idea where to get that license. What is the deal here?
> 3. What are the config difference between configure this card with passthrough vs vGPU?
> 
> 
> Currently I configure it with passthrough based one one article and I am able to spun up with and I can see nvidia card exposed to vm. (I used iommu and vfio based driver) so if this card support vGPU then do I need iommu and vfio or some other driver to make it virtualize ?
> 
> Sent from my iPhone
>