XCP-ng 8.3 updates announcements and testing

TeddyAstie

@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=0 to 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 ?

ph7

@gduperrey

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

dthenot

@ph7 It's only enabled for the two yum command with the --enablerepo explicitly used.
It's disabled in the config otherwise.
No need to do anything

gduperrey

Update published: https://xcp-ng.org/blog/2025/03/12/march-2025-maintenance-update-for-xcp-ng-8-3/

Thank you for the tests!

manilx

@gduperrey 1 HomeLab-Pool (via cli: yum update and reboot), 3 Business-Pools (via RPU), total 7 servers updated without issues.

bvitnik

@TeddyAstie Is the list of "issues and limitations" of nested virtualization under Xen documented somewhere?

stormi

@bvitnik It's better to consider it as working by chance in some scenarios, but I think Teddy can give you details

archw

@gduperrey
Is a reboot required for this batch of updates?

Andrew

@archw Yes.

archw

@Andrew
Thanks!