External Monitoring Tools Unable to Retrieve ESXi Host Serial Number from vCenter MOB (Managed Object Browser)

Products

• VMware vSphere ESXi

Issue/Introduction

• RVTools does not display the serial number of ESXi hosts when connected to vCenter.
• The serial number is visible in the vSphere Client but not reflected in RVTools output.
• In the ESXi host’s Managed Object Browser (MOB) page, the serial number is correctly populated.
• In the vCenter MOB page, the serial number appears as "unset". Below is the path for getting serial Number in MOB:
  content -> rootFolder -> childEntity -> hostFolder -> childEntity [select appropriate host] -> host -> hardware -> systemInfo -> serialNumber

• The serial number remains available under the following path in the vCenter MOB:
  content -> rootFolder -> childEntity -> hostFolder -> childEntity [select appropriate host] 
-> host -> hardware -> systemInfo -> otherIdentifyingInfo -> SerialNumberTag

Environment

VMware vSphere ESXi

Cause

• The serialNumber property is not explicitly saved in the vCenter database (VCDB) during host synchronization. As a result, parts of the host configuration that are not stored in VCDB lose their values after a vpxd service restart, until the next full host sync occurs.
• This behavior is by design, as the serialNumber field is an optional property and not persisted in the database.

Resolution

Follow the below steps to resolve the issue:

Option 1

• Restart the management agents on ESXi host.
  Restarting Management Agents in ESXi

Option 2

• Disconnect and Reconnect the ESXi Host
  • From the vSphere Client, disconnect and then reconnect the ESXi host to vCenter Server.
  • This forces a full host synchronization, refreshing the hardware information including the serial number.

Verify Serial Number in vCenter MOB

• Access the vCenter MOB and confirm that the serial number appears correctly under the path:
  content -> rootFolder -> childEntity -> hostFolder -> childEntity [select appropriate host] 
-> host -> hardware -> systemInfo -> otherIdentifyingInfo -> SerialNumberTag

Validate Using RVTools

• Access the vCenter MOB and confirm that the serial number appears correctly under the path:

Alternative Tools

While Broadcom does not offer a direct replacement for RVTools, the following supported options can generate equivalent reports (including information available under vInfo and vHost tabs in RVTools):

• vSphere PowerCLI – Official VMware/Broadcom-supported PowerShell module for inventory, configuration, and performance data collection.
• vRealize Operations (vROps) – Comprehensive monitoring and reporting platform integrated with vCenter and ESXi.
• vSphere API / REST API – Enables programmatic access to the same information for integration with custom reporting tools.

Additional Information

• Disconnecting and reconnecting the host refreshes vCenter’s hardware inventory, resolving the issue.
• This behavior is expected and works as designed for the serialNumber property.
• External monitoring tools may fail to display the serial number when vCenter MOB shows the value as unset.