Le mar. 20 juin 2023 à 16:31, Mahendra Paipuri <mahendra.paipuri@cnrs.fr> a écrit :

Thanks Sylvain for the pointers.

One of the questions we have is: can we create MIG profiles on the host and then attach each one or more profile(s) to VMs? This bug [1] reports that once we attach one profile to a VM, rest of MIG profiles become unavailable. From what you have said about using SR-IOV and VFs, I guess this should be possible.

Correct, what you need is to create first the VFs using sriov-manage and then you can create the MIG instances.

Once you create the MIG instances using the profiles you want, you will see that the related available_instances for the nvidia mdev type (by looking at sysfs) will say that you can have a single vGPU for this profile.

Then, you can use that mdev type with Nova using nova.conf.

That being said, while this above is simple, the below talk was saying more about how to correctly use the GPU by the host so please wait :-)

I think you are talking about "vGPUs with OpenStack Nova" talk on OpenInfra stage. I will look into it once the videos will be online.

Indeed.

-S

[1] https://bugs.launchpad.net/nova/+bug/2008883

Thanks

Regards

Mahendra

On 20/06/2023 15:47, Sylvain Bauza wrote:

Le mar. 20 juin 2023 à 15:12, PAIPURI Mahendra <mahendra.paipuri@cnrs.fr> a écrit :

Hello Ulrich,

I am relaunching this discussion as I noticed that you gave a talk about this topic at OpenInfra Summit in Vancouver. Is it possible to share the presentation here? I hope the talks will be uploaded soon in YouTube. 

We are mainly interested in using MIG instances in Openstack cloud and I could not really find a lot of information by googling. If you could share your experiences, that would be great.

Due to scheduling conflicts, I wasn't able to attend Ulrich's session but his feedback will be greatly listened to by me.

FWIW, there was also a short session about how to enable MIG and play with Nova at the OpenInfra stage (and that one I was able to attend it), and it was quite seamless. What exact information are you looking for ?

The idea with MIG is that you need to create SRIOV VFs above the MIG instances using sriov-manage script provided by nvidia so that the mediated devices will use those VFs as the base PCI devices to be used for Nova.

Cheers.

Regards

Mahendra

---

De : Ulrich Schwickerath <Ulrich.Schwickerath@cern.ch>
Envoyé : lundi 16 janvier 2023 11:38:08
À : openstack-discuss@lists.openstack.org
Objet : Re: 答复: Experience with VGPUs

 

Hi, all,

just to add to the discussion, at CERN we have recently deployed a bunch of A100 GPUs in PCI passthrough mode, and are now looking into improving their usage by using MIG. From the NOVA point of view things seem to work OK, we can schedule VMs requesting a VGPU, the client starts up and gets a license token from our NVIDIA license server (distributing license keys is our private cloud is relatively easy in our case). It's a PoC only for the time being, and we're not ready to put that forward as we're facing issues with CUDA on the client (it fails immediately in memory operations with 'not supported', still investigating why this happens).

Once we get that working it would be nice to be able to have a more fine grained scheduling so that people can ask for MIG devices of different size. The other challenge is how to set limits on GPU resources. Once the above issues have been sorted out we may want to look into cyborg as well thus we are quite interested in first experiences with this.

Kind regards,

Ulrich

On 13.01.23 21:06, Dmitriy Rabotyagov wrote:

To have that said, deb/rpm packages they are providing doesn't help much, as:

* There is no repo for them, so you need to download them manually from enterprise portal

* They can't be upgraded anyway, as driver version is part of the package name. And each package conflicts with any another one. So you need to explicitly remove old package and only then install new one. And yes, you must stop all VMs before upgrading driver and no, you can't live migrate GPU mdev devices due to that now being implemented in qemu. So deb/rpm/generic driver doesn't matter at the end tbh.

пт, 13 янв. 2023 г., 20:56 Cedric <yipikai7@gmail.com>:

Ended up with the very same conclusions than Dimitry regarding the use of Nvidia Vgrid for the VGPU use case with Nova, it works pretty well but:

- respecting the licensing model as operationnal constraints, note that guests need to reach a license server in order to get a token (could be via the Nvidia SaaS service or on-prem)
- drivers for both guest and hypervisor are not easy to implement and maintain on large scale. A year ago, hypervisors drivers were not packaged to Debian/Ubuntu, but builded though a bash script, thus requiering additional automatisation work and careful attention regarding kernel update/reboot of Nova hypervisors.

Cheers

On Fri, Jan 13, 2023 at 4:21 PM Dmitriy Rabotyagov <noonedeadpunk@gmail.com> wrote:
>
> You are saying that, like Nvidia GRID drivers are open-sourced while
> in fact they're super far from being that. In order to download
> drivers not only for hypervisors, but also for guest VMs you need to
> have an account in their Enterprise Portal. It took me roughly 6 weeks
> of discussions with hardware vendors and Nvidia support to get a
> proper account there. And that happened only after applying for their
> Partner Network (NPN).
> That still doesn't solve the issue of how to provide drivers to
> guests, except pre-build a series of images with these drivers
> pre-installed (we ended up with making a DIB element for that [1]).
> Not saying about the need to distribute license tokens for guests and
> the whole mess with compatibility between hypervisor and guest drivers
> (as guest driver can't be newer then host one, and HVs can't be too
> new either).
>
> It's not that I'm protecting AMD, but just saying that Nvidia is not
> that straightforward either, and at least on paper AMD vGPUs look
> easier both for operators and end-users.
>
> [1] https://github.com/citynetwork/dib-elements/tree/main/nvgrid
>
> >
> > As for AMD cards, AMD stated that some of their MI series card supports SR-IOV for vGPUs. However, those drivers are never open source or provided closed source to public, only large cloud providers are able to get them. So I don't really recommend getting AMD cards for vGPU unless you are able to get support from them.
> >
>