Unable to Hot-Add CPU with error "Requested number of processors 2 is more than 1 processors this virtual machine is configured for"

Products

• VMware vSphere ESX 7.x
• VCF Operations/Automation (formerly VMware Aria Suite)
• VMware vCenter Server

Issue/Introduction

• Hot-Add CPU failed when attempts to change the CPU count in the VM settings vCenter UI with error "Requested number of processors 2 is more than 1 processors this virtual machine is configured for"
  
• The VM resize operation failed with Aria Automation with error "Error from vCenter: Requested number of processors 2 is more than 1 processors this virtual machine is configured for."

 

Environment

• vSphere 7.x
• vSphere 8.x
• Aria Automation 8.x

Cause

The VM was deployed with an advanced parameter cpuid.coresPerSocket = "2" but the VM is configured for only 1 vCPU.

This error occurs when a VM is assigned more vCPU than the physical host supports or the hypervisor allows in its current configuration.

The total number of vCPUs is calculated by multiplying the number of Sockets by the Cores per Socket.

This error triggered because there was a mathematical mismatch in the requested configuration. Specifically, the requested "Cores per Socket" (2) exceeded the "Total Virtual CPUs" currently allocated to the VM (1). A VM cannot have more cores in a single socket than the total number of processors assigned to the entire machine.

For more details on how to set the correct vCPU and cores per socket settings please see this article:

Setting the number of cores per CPU in a virtual machine

Resolution

Power Off the Virtual Machine and then add extra vCPU and then Power On.

Or from Aria Automation select the option Reboot Machine when using the Resize Action.