Disable virtualization on cluster node


New Member
Nov 11, 2020

I have 3 node cluster and I would like to disable virtualization support on one node due to licensing issues.
However I would like to keep Proxmox GUI on this node to be able to manage Ceph from the GUI.

Every node has a ROMED8-2T motherboard with an EPYC 74F3 processor (This CPU is only for testing purposes, in production deployment the node with blocked virtualization will have some other milan cpu).

I have disabled SVM in BIOS and the virtualization kind of doesn't work? Starting a VM leads to an error, but after several halt and start cycles it boots up properly. I thought that Proxmox can't do qemu soft only virtualization and always uses KVM which require hardware virtualization. Also I guess that Proxmox can't enable SVM extensions on runtime (when it's disabled in BIOS settings).

Checking MSR register confirms SVM is disabled:

# modprobe msr
# rdmsr --bitfield 4:4 0xc0010114 2>/dev/null

KVM module is loaded and Proxmox thinks that virtualization is working properly. KVM should print something like kvm disabled by bios to dmesg when SVM is disabled but there is no such entry. I don't know if this is a KVM issue or something in the CPU isn't set right.

Blacklisting KVM module didn't do anything, the module is still being loaded on boot.

What am I missing?

Kind regards
May i just ask what licencing issues you're reffering to?
Licensing issues with software installed inside virtual machines. Some of them forbid use of more than two nodes. I initially thought about manually installing quorum device and cephfs on the third system, but now I'm trying more natural approach where proxmox handles quorum device and ceph but can't perform any virtualization.

Just an idea: disableing the kvm module in boot cmd in grub config?
I've managed to redirect loading modules to /bin/true (blacklisting didn't work):
In file: /etc/modprobe.d/disabled.conf:

install kvm_intel /bin/true
install kvm_amd /bin/true
install kvm /bin/true

Proxmox seems to be working stable without kvm module. VMs can't be started as expected


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