SDDC Manager vCenter Upgrade Post-Validation Fails with "Existing SSH key not found"

Products

• VMware SDDC Manager / VCF Installer

Issue/Introduction

vCenter upgrade to version 9.x or higher via SDDC Manager appears successful in the vSphere Client/VAMI.

The SDDC Manager task "VCENTER UPGRADE POST VALIDATION" fails or remains in a blocked state.

Error Message: Reason is: Existing SSH key not found for host [vCenter_FQDN]
                          Reference Token: INN3U1

Environment

vCenter server Appliance 9.x

Cause

This issue typically occurs when there is a mismatch or authentication failure between the SDDC Manager and the newly upgraded vCenter appliance.

 

Resolution

1. Verify Upgrade Success: Confirm the vCenter is running the correct target build (e.g., 9.0.2.0100) via the VAMI (port 5480).
   
   
2. Validate SSH State:
   
   
   • Ensure SSH is enabled on the vCenter appliance.
     
     
   • Check /etc/ssh/sshd_config to ensure PubkeyAuthentication yes is set.
     
     
3. Check for Name Mismatches: If the vCenter has undergone a recent name change or was previously showing as "localhost", ensure that the SDDC Manager inventory correctly reflects the current FQDN and that SSH keys have been re-exchanged.
   
   
4. Mark Task as Success: If the environment is confirmed healthy and the error is determined to be a false positive due to the naming incident, the upgrade task in the SDDC Manager database may need to be manually updated to COMPLETED_WITH_SUCCESS.

Additional Information

Pre-Upgrade Check Failure: Method Invocation Error – Unsupported Digital Envelope Routine

Error: "Could not authenticate to source appliance OS on address" when attempting vCenter upgrade