Incorrect allocation of vCPUs to virtual sockets during Virtual Machine provisioning via an external orchestration engine, resulting in CPU scheduling inefficiencies.

Products

• VMware vCenter Server

Issue/Introduction

Deploying vm's using an external orchestration engine results in incorrect allocation of vCPUs to virtual sockets during Virtual Machine provisioning via an external orchestration engine ("LEON"), resulting in CPU scheduling inefficiencies.

Environment

vSphere 7.x

vSphere 8.x

vSphere 9.x

Cause

The external orchestration engine ("LEON") forces an arbitrary virtual socket count during VM provisioning, overriding the default topology behavior.

 

 

Resolution

To fix this follow one of the below steps:

• Modify the provisioning blueprint or scripting logic within the LEON tool to explicitly declare the numCoresPerSocket attribute during the VM creation/cloning API execution.
• Convert the source template to a Virtual Machine, adjust the CPU configuration by adding advanced parameter cpuid.coresPerSocket value 1 and then convert the vm back to template and use this to deploy.
• (OR)Edit the vm settings and  set 'Assigned at power on'  on the  CPU Topology.

Additional Information

Rightsizing virtual machines on ESXi 8.0: vCPU, memory, and CPU topology guidance

Virtual Machine vCPU and vNUMA Rightsizing – Guidelines