Duplicate UUIDs Observed Across ESXi Hosts in Multiple vCenter Environments

Products

• VMware vSphere ESXi

Issue/Introduction

When managing ESXi hosts across multiple vCenter environments, duplicate UUIDs may be observed among different hosts.

In this scenario, certain hosts in separate vCenter environments were found to share identical UUIDs, leading to host identity conflicts within the VMware infrastructure.

Example:

• Host A in X vCenter reports the same UUID as

• Host A in Y vCenter

Each vCenter environment contains ESXi hosts managed independently.

Environment

VMware vSphere ESXi 8.x

Cause

The issue occurs because the ESXi hosts were provisioned using a template-based deployment process in a vBlock environment.
This approach resulted in duplicate SMBIOS UUIDs being assigned to multiple servers during deployment.

ESXi derives its host UUID from the System Management BIOS (SMBIOS) information provided by the underlying hardware. When the same SMBIOS UUID is used across multiple hosts, ESXi registers identical system identifiers, leading to duplication across environments.

Resolution

This issue originates from a hardware-level misconfiguration where identical SMBIOS UUIDs were assigned to multiple servers.

Recommended Actions:

1. Engage the hardware vendor to correct the SMBIOS UUIDs for all affected hosts. Each physical host must have a unique hardware identifier.

2. Once the SMBIOS UUIDs have been corrected, perform a clean reinstallation of ESXi (do not retain existing configurations).

   • During installation, ESXi automatically reads the updated UUID from the hardware and registers it as a unique system UUID.

3. Do not manually modify UUIDs within ESXi configuration files.

   • Editing system files to alter UUIDs is not supported by Broadcom and may cause issues related to:

     • Licensing

     • vSphere Distributed Switch (vDS) configuration

     • High Availability (HA) and Distributed Resource Scheduler (DRS) functionality

Additional Information

The ESXi host UUID is retrieved during boot from the SMBIOS. This UUID must be unique for every physical host to ensure accurate identification and functionality within vCenter, vSphere services, and other VMware ecosystem components.