Need help with Proxmox hotplug CPU issue

[ankur.kumar]

Hey everyone,

I'm having an issue with hotplugging CPUs in Proxmox. Here's what's happening:

1. Set a limit of 6 vCPUs.
2. Launched a Windows VM with 2 vCPUs.
3. Enabled NUMA and hotplug options in the VM settings.

When I try to increase the number of vCPUs using the edit option in the hardware section, the latest configurations show up in an orange line instead of actually increasing the number of vCPUs. Additionally, if I restart the VM from the console, the vCPU count remains unchanged, but if I reboot it from the Proxmox dashboard, the vCPU count increases.


Any suggestions on how to fix this would be greatly appreciated!

Thanks!

 

[gfngfn256]

That is the expected behavior. Changes that can only be made on a stopped VM, will wait until Proxmox sees them stopped & then starts them again. The VM rebooting "itself" does not fulfill this condition. If you stop the VM - you'll see the updated config act.

Edit: Read here for the correct implementation for CPU hotplugging.

 

[ankur.kumar]

Thanks @gfngfn256 for the response! I appreciate the clarification. But if I need to manually stop and start the VM for changes to take effect, what's the point of hotplugging? Just trying to understand the rationale behind it. Thanks again!"

 

[gfngfn256]

As above (edited) I pressed the "post" before I finished typing .....