XCP-ng 8.3 updates announcements and testing
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Home host updated successfully, no issue.
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installed on 2 test machines
Machine 1:
Intel Xeon E-2336
SuperMicro board.Machine 2:
Minisforum MS-01
i9-13900H
32 GB Ram
Using Intel X710 onboard NICBoth machines installed fine and all VMs came up without issue after.
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Latest test updates were applied to three-node home lab pool (3 x Dell OptiPlex SFF 7040 i7-6700/48GB RAM/256GB NVMe boot drive/TrueNAS Core 10Gbps-attached NFS shared storage) without incident. VMs appear to running normally, live migration between hosts works fine and no apparent problems so far.
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The update went fine and everything is working fine.
@gduperrey said in XCP-ng 8.3 updates announcements and testing:
xapi: Re-enabled nested virtualization in 8.3, with the same limitations as in 8.2.
Since I keep bothering with nested virtualization here on the forum, I of course immediately tried the support in 8.3
Setup:
- HW XCP-ng 8.3
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- Nested XCP-ng 8.3
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- Windows Server 2025
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- Debian 12.9
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Windows installation on the nested hypervisor went ok and the system seems to be working fine.
The problem occurred with Debian. ISO 12.9 netistall, UEFI was used. The system boots up and shows the notorious install screen: Graphic install, Install ... Regardless of the type of installation chosen, immediately after starting it, nested hypervisor XCP-ng 8.3 crashes and reboots. By the way, this problem with Debian is also on VMware - if I use nested XCP-ng 8.3 there, the Debian installation crashes it just the same. -
@abudef Note that even with this update, nested virtualization is still not really supported in XCP-ng 8.3.
It's there, you can enable it at your own risk. It broke due to some change in XAPI (even though Xen hypervisor had "support" for it).
It never actually got removed from Xen hypervisor (it was marked experimental in Xen 4.13 used in XCP-ng 8.2, it is also the case for Xen 4.17), although nothing really changed, it still has the same issues and limitations as said.The current state of nested virtualization in Xen is quite clumsy and there are future plans to remake it properly from ground without taking shortcuts and have proper tests to back it.
Aside that, after some experiments, it seems that mostly nested EPT is incomplete/buggy, so your L1 hypervisor should not rely on it. You should add
hap=0to nested XCP-ng Xen cmdline. Beware that it will imply a pretty large performance hit, but I had more consistent results with this.
I am quite suprised that Windows works while Linux don't, maybe it is somewhat related to PV drivers ? -
I updated my test host and all seems to work fine.
But I have 1 question:
Do I need to disable the testing repo or is it removed at the reboot?yum clean metadata --enablerepo=xcp-ng-testing
yum update --enablerepo=xcp-ng-testing
reboot[10:33 x1 ~]# yum repolist Inlästa insticksmoduler: fastestmirror Loading mirror speeds from cached hostfile Excluding mirror: updates.xcp-ng.org * xcp-ng-base: mirrors.xcp-ng.org Excluding mirror: updates.xcp-ng.org * xcp-ng-updates: mirrors.xcp-ng.org förråds-id förrådsnamn status xcp-ng-base XCP-ng Base Repository 4 376 xcp-ng-updates XCP-ng Updates Repository 125 repolist: 4 501 -
@ph7 It's only enabled for the two yum command with the
--enablerepoexplicitly used.
It's disabled in the config otherwise.
No need to do anything -
Update published: https://xcp-ng.org/blog/2025/03/12/march-2025-maintenance-update-for-xcp-ng-8-3/
Thank you for the tests!
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@gduperrey 1 HomeLab-Pool (via cli: yum update and reboot), 3 Business-Pools (via RPU), total 7 servers updated without issues.
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@TeddyAstie Is the list of "issues and limitations" of nested virtualization under Xen documented somewhere?
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@bvitnik It's better to consider it as working by chance in some scenarios, but I think Teddy can give you details
