Errors while upgrading vCenter to 8.x "VMDir Replication between partners is not working"

Products

• VMware vCenter Server

Issue/Introduction

• While upgrading a standalone vCenter server which was earlier part of a ELM (Enhanced Linked Mode) set-up fails with below error:
  
  "Pre-upgrade check failed due the following problem: This operation is not allowed in the current state as operation 'None' is already in progress."

• While performing the prechecks in Stage2, error  comes  as
  
  

  VMDir Replication between partners is not working.
Make sure vmdir service is reachable and started in partner nodes and this node before continuing.
  
  
  
  

• The VMDir replication pre-check failed because the system is either attempting to replicate with a stale partner vCenter entry (a server was deleted but not decommissioned) or because a currently active ELM partner is experiencing a VMDir replication failure.
  
  
• Running the below command to check the replication partners still shows the old deleted vCenter server
  # /usr/lib/vmware-vmdir/bin/vdcrepadmin -f showpartners -h localhost -u administrator -w 'Administrator_Password'


• The requirements-upgrade-runner.log gives the below error.

Log Location: /var/log/vmware/upgrade/requirements-upgrade-runner.log

[YYYY-MM-DDTHH:MM:SS] INFO upgrade_commands Reporting source preupgrade result errors and warnings.

[YYYY-MM-DDTHH:MM:SS] ERROR upgrade_commands Pre-upgrade checks errors:
[YYYY-MM-DDTHH:MM:SS] ERROR upgrade_commands {'text': {'id': 'upgrade.vmafd.precheck.error.text', 'translatable': 'VMDir Replication between partners is not working', 'localized': 'VMDir Replication between partners is not working'}, 'description': {'id': 'upgrade.vmafd.precheck.error.description', 'translatable': 'VMDir Replication between partners is not working', 'localized': 'VMDir Replication between partners is not working'}, 'resolution': {'id': 'upgrade.vmafd.precheck.error.resolution', 'translatable': 'Make sure vmdir service is reachable and started in partner nodes and this node before continuing', 'localized': 'Make sure vmdir service is reachable and started in partner nodes and this node before continuing'}, 'problemId': None}

• Running the VCF Diagnostic Tool for vSphere (VDT) shows failure in VMdir Functionality check as shown below.

   VMdir Replication Checks
            [FAIL]    VMdir Partner Check

Environment

^{VMware vCenter Server 7.x}

Cause

^{The VMDir replication pre-check failed because the system is either attempting to replicate with a stale partner vCenter entry (a server was deleted but not decommissioned) or because a currently active ELM partner is experiencing a VMDir replication failure.}

Resolution

Note: This should be followed only on the vCenter Servers where the replication partner is deleted. If the partner vCenter is still in active state, please contact Broadcom support for further investigation.

 ENSURE OFFLINE SNAPSHOTS OF ALL VCs IN THE SSO DOMAIN AND/OR BACKUPS ARE IN PLACE IMMEDIATELY PRIOR TO THIS OPERATION.

• Follow the Below KB to decommission the deleted vCenter server.
  Using the cmsso command to unregister vCenter with External PSC or vCenter with Embedded PSC from Single Sign-On