Cores per socket are automatically set to 1 by vRA Flavor, which conflicts with automated "NUMA" CPU topology feature in ESXi 8

Products

• VMware Aria Suite

Issue/Introduction

vSphere 8.0 provides intelligent selection of VM hardware values such as Cores per Socket:

• Configure the CPU Topology of a Virtual Machine in vCenter 8.X
  "By default, the ESXi host automatically selects a virtual topology that aligns with the underlying hardware”

Cores per Socket	Select whether you want the system to automatically assign the cores per socket or manually specify the numbers of cores per socket.

• However, when using Flavor Mapping for sizing in Aria Automation  versions 8.14.0 -> 8.16.1, Aria Automation may default to setting 1 core per socket
• In such situation, cd to the directory of VM then run "grep -i coresPerSocket *.vmx", to find the string coresPerSocket in VM's configuration file .vmx, we see this line,
  cpuid.coresPerSocket = "1"
• vRA 8.16.0 sets cores per socket on newly-built VMs using the (mandatory) cores per socket setting on the RHS of Flavor Mappings screen.
• How can we set newly-built VM cores per socket automatically using NUMA?

Environment

• VMware Aria Automation 8.14.0 -> 8.16.1
• VMware vSphere 8.0.x

Cause

From Aria Automation 8.14.0 -> 8.16.1,

• Saving flavor mapping without mentioning the ' Cores per Socket ' configuration in UI or just specifying the explicit CPU, RAM values in VCT defaults the value of coreCount as ' 1 '

Resolution

Resolution

• The issue is solved in Aria Automation 8.16.2, with additional fixes for cores per socket (regarding day2 actions) included in version 8.18.1

Workaround

• As a workaround, you may select the CPU, RAM etc. manually in the cloud template (i.e. not using a Flavor Mapping)
• In this case, the Cores per Socket value is unset and will be chosen dynamically by vSphere
• For a deployed VM, shutdown the VM first, then right click the VM -> VM Options -> CPU Topology -> Cores per Socket , manually change the value from "Assigned at power on" to a desired value, such as 2, 4, 8....