Nested Virtualization of Windows Hyper-V on XCP-ng
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I am finding myself in this really unfortunate situation. We want to use Microsoft Connected Cache which requires Hyper-V. Microsoft Connected Cache is a way to cache inTune installation packages to reduce internet usage.
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Is there any news about Nested Hyper-V support?
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I'm not aware about any progress on that direction. It's more like an upstream Xen Project question by the way, you might ask on the Xen Project Matrix community: https://xenproject.org/help/matrix/
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@olivierlambert Okay. Thank you.
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@olivierlambert thanks. I asked. No estimate.
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Though a little old this is the only thread that seems applicable to my needs right now... Do we have any ideas on when this might become available in Xen?
I have a client that needs to use part of Hyper-V for an application they are using. Are there any workarounds? I see Proxmox seems to support this, but I haven't tested.
Thanks!
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There was a talk in Xen Summit about what needs to be done to complete Nested Virtualization support, but I don't know if anyone in the Xen Project followed-up.
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@stormi Bummer... Because I really could use the ability to run Hyper-V in a Windows Server VM... It's needed for a certain application that a client of mine uses.
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@FTSSupport I'd first consider talking to the client and/or the clients vendor that is requiring this. Nested virtualization, even on setups that work, is NEVER recommended for something that requires good up time and reliability, so it might be best to avoid this.
I have had issues with nested virt in ProxMox as well, admittedly less than in XCP-ng, but it's still not good enough on either that I'd use it consistently.
Is there a reason the application needs Hyper-V? The reason I ask is, I've had something similar due to a vendor who required ESXi for their VMs. Turns out there was no good reason for that and we ended up having to spend a ton of money for no real benefit. Has created more headaches down the road too w/ lack of central backups, etc... and massive wasted resources (time, money, all of the above). The vendor has since said they'll help us move to XCP-ng, but it's a big process and there was no reason for ESXi in the first place.
So maybe, just maybe, there's a chance the vendor/application developer can be convinced otherwise? One of the points of virtualization is keeping options open.
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@planedrop Just to keep things cohesive in these threads, I'm linking my response https://xcp-ng.org/forum/post/81103
But yeah I may take your advice and call the vendor.
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i was searching for nested virtualization on windows vm because i wanted to install docker desktop and nested virtualization should have been enabled
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@AlexanderK Right, which in some ways in similar in what I'm needing, because there are applications that need Hyper-V.
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@FTSSupport Gotcha, yeah I think the first step would be finding out if there are workarounds from the vendor, then go from there if there aren't. May just require spinning up a physical Hyper-V box, but that would definitely suck. The entire idea of hypervisors was to not have to run so many different bare metal installs of things lol.
Good luck!
I may play around with nested Hyper-V here soon to see what I can get working, but honestly I'd still avoid it EVEN IF we can get it working stable, could be a headache to troubleshoot down the road.
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@planedrop In general, the fact is that the current XCP-ng 8.3 RC1 and XenServer 8 simply do not support any kind of nested virtualization. For example, when I want to try a mock setup of say 5 hypervisors, I just don't buy or dedicate 5 hw servers and rather make virtualized hypervisors. And for the record, I'm referring to the lab environment for debugging configurations and scenarios, not production.
P. S.: In more legacy Xen, which is part of XCP-ng 8.2, nested virtualization works.
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Sure but the solution to that is usually to buy a single server and then try each hypervisor on it in a lab type setup to see which you prefer the best.
I still agree that it would be nice to have 1 box that runs them all, for sure, but there aren't any that can actually do that.
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@abudef said in Nested Virtualization of Windows Hyper-V on XCP-ng:
@planedrop In general, the fact is that the current XCP-ng 8.3 RC1 and XenServer 8 simply do not support any kind of nested virtualization.
Indeed.
Actually, Xen never officially supported Nested Virtualization. It was experimental, and broke when other needed changes were made to Xen. Now there's work to be done to make it fully supported, and this won't happen before the final release of XCP-ng 8.3. This will be documented in the release notes.
This is also an issue for us internally as we create a lot of virtual pools for our tests.
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@stormi Excited to see more progress on this for sure.
Still should never be done in a production setup though so I don't think there should be any rush ha!
Would be very cool to have in lab environments though.
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@planedrop Yeah Appreciated! I'm going to do a conference call with the vendor next week hopefully... They won't talk with me since I'm an MSP for my client... Stupid...
I'm experimenting with Nested virtualization with Proxmox... The application is installing but throwing errors, but I don't know if that's because of it being nested or if it's just throwing errors...
Regardless I may try XCP-NG 8.2 latest and see how it reacts with nested virtualization and just stick with that if it works... It'll be easier to backwards migrate everything from 8.3 to 8.2 than moving to Proxmox (I think?)
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@FTSSupport Should be easier to move back to 8.2 than Proxmox, yes. I'm still not sure it's going to work that well though, either in 8.2 or in Proxmox. I've just never had a good experience with nested virt.
I got it working well on a Hyper-V setup once, but the nested VM still had some odd issues, bad latency, and a few other things, and that was all Windows based stuff so it was kinda a best case scenario.
Good luck with the vendor, hopefully they can be convinced that it will work just fine on other hypervisors.
One vendor I worked with that required ESXi for their Windows VM finally changed their minds and worked w/ me to do some validation on XCP-ng. After we ran through a ton of testing (this was a very high bandwidth/data usage platform with strict requirements) the engineers were flabbergasted because XCP-ng performed so much better lol. I was like "you're really surprised something is faster than bloated ESXi??"
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@planedrop Here's hoping! Though I'm not hopeful because their installer application hooks into Hyper-V and creates an Ubuntu server on there and then extract tarballs into it... It's very strange.
