Error: "Failed to get mapping vmnic for uplink <uplink-name>" during VxRail host configuration

Products

• VMware vCenter Server

Issue/Introduction

• During VxRail host configuration or cluster expansion, the task fails at the network validation stage.
• The Dell VxRail host configuration UI shows the error: Failed to get mapping vmnic for uplink <uplink/LAG name> in nic_mappings.
  
• The uplink highlighted in the error does not exist in the DVS to which the host is being added.
  
  
• VxRail logs show networks_utils.py querying get_dc_pgs_default_config()  returning port groups which use the uplink mentioned in the error.
  

Environment

• VxRail Manager
• VMware vCenter Server

Cause

This issue occurs when VxRail Manager queries vCenter for a specific port group name at the Datacenter level. In environments where ACI pushes duplicate port group names across multiple DVS within the same datacenter, vCenter returns multiple matches. VxRail Manager selects an incorrect object from the result, leading to a failure to map the active uplinks correctly.

Resolution

1. Identify all port groups in the vCenter Datacenter inventory that share the name reported in the logs
2. Rename the duplicate port groups on non-target Distributed Switches to ensure that each port group name is unique at the Datacenter level.
3. If using ACI, adjust the EPG naming convention or VMM domain settings to ensure unique names are pushed to vCenter.
4. Retry the host configuration task in VxRail Manager.

Note: If unable to rename the port groups due to ACI VMM or other limitations within the vCenter inventory contact the Dell VxRail support team. They can provide further investigation into the VxRail Manager selection logic or explore alternative deployment workarounds.

Additional Information

• For general information on port group naming requirements in VCF environments, see Article 421905.