Anyone familiar with KVM nested virtualization?
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I have Fedora 26 running as a guest on Hyper-V 2016.
I'm wondering if it's possible to still enable nested virtualization in my Fedora 26 VM? Everything I've come across was if Fedora was running on the bare-metal, and some configurations I come across doesn't exist on my installation. I'm thinking it's because of that.
I can't figure it out.
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@tim_g
KVM only supports hardware virtualization. So should be able to take advantage of using paravirtualization if you use Xen instead.
I found a couple of sites about enabling nested virtualization in KVM.
When Fedora is running on bare-metal
https://fedoraproject.org/wiki/How_to_enable_nested_virtualization_in_KVMIf you want to run Hyper-V has a KVM guest
https://ladipro.wordpress.com/2017/02/24/running-hyperv-in-kvm-guest/ -
@black3dynamite said in Anyone familiar with KVM nested virtualization?:
@tim_g
KVM only supports hardware virtualization. So should be able to take advantage of using paravirtualization if you use Xen instead.
I found a couple of sites about enabling nested virtualization in KVM.
When Fedora is running on bare-metal
https://fedoraproject.org/wiki/How_to_enable_nested_virtualization_in_KVMIf you want to run Hyper-V has a KVM guest
https://ladipro.wordpress.com/2017/02/24/running-hyperv-in-kvm-guest/So if I understand correctly, KVM has to be the one on bare-metal in any case?
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@tim_g Yes.
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@black3dynamite said in Anyone familiar with KVM nested virtualization?:
@tim_g Yes.
Okay, that explains a lot.
Thanks for the help and clarification (and links)!
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@tim_g said in Anyone familiar with KVM nested virtualization?:
So if I understand correctly, KVM has to be the one on bare-metal in any case?
No, that's always a factor of the underlying hypervisor, not of the one on top. All hypervisors support BEING nested. But only some hypervisors allow for nesting on top of themselves. KVM will work on top of ESXi for sure, and definitely not on older Hyper-V. Not sure about 2016.
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What all hypervisors that are not Xen need, is hardware from the CPU to do their virtualization. So what they need from their underlying hypervisor is for the entire CPU, not just part of it, to be virtualized. The problem with most hypervisors is that the "pc appearance" that they create on which an OS is installed is a less capable processor than the real one that the HV is running on. So while the HV is getting virtualization enabled hardware, the OS normally is not. But if the HV passes that through, then the secondary HV will be fully capable as well.
