ESXi Host Client inadvertently sets cpuid.coresPerSocket to 1 when saving virtual machine settings

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

When a virtual machine is configured with default CPU topology settings (where the cpuid.coresPerSocket entry does not exist in the .vmx file), editing and saving the virtual machine settings using the ESXi Host Client results in the explicit addition of cpuid.coresPerSocket = "1" to the configuration.

This behavior occurs even if the user does not manually modify the CPU topology settings in the user interface.

You may observe a reconfigure task in the var/run/log/hostd.log file similar to the following:

YYYY-MM-DDTHH:MM:SS In(166) Hostd[2099567]: [Originator@6876 sub=Vimsvc.TaskManager opID=esxui-98fd-4361 sid=5236ed6a user=root] Task Created : haTask-5-vim.VirtualMachine.reconfigure-2207015668

Environment

VMware vSphere ESXi 8

Cause

The ESXi Host Client user interface interprets the absence of the cpuid.coresPerSocket parameter as a value of 1 by default. When the Save button is clicked in the settings wizard, this default value is written to the virtual machine configuration file, changing the setting from automatic assignment to a fixed value of 1 core per socket.

Resolution

To resolve this issue and revert the configuration to its default state, perform the following steps using the vSphere Client:

1. Log in to the vSphere Client.

2. Right-click the affected virtual machine and select Edit Settings.

3. Navigate to the VM Options tab.

4. Expand CPU Topology.

5. Locate the Cores per Socket setting.

6. Change the value to Assigned to power on.

7. Click OK to save the changes.

To prevent this issue, use the vSphere Client instead of the ESXi Host Client when editing virtual machine settings.

Additional Information

Japanese version: ESXi Host Client で仮想マシンの設定を保存すると cpuid.coresPerSocket が 1 に変更される(425837)