Error: VMDir Replication is not working between partners during vCenter upgrade

Products

• VMware vCenter Server

Issue/Introduction

• When updating vCenter Server  in an Enhanced Linked Mode (ELM) setup, the pre-check fails with: 'VMDir Replication is not working between partners'. 
• This occurs during sequential node updates, even when vdcrepadmin shows a 'Normal' status

• We verify the VMDir replication partner status and VMDir state in vCenter Server using the vdcrepadmin command-line utility, which shows a healthy status. :

  ./vdcrepadmin -f showpartnerstatus -h localhost -u administrator -w 'Administrator_Password'

########################################
ShowPartners
ldap://###.###.###
ldap://###.###.###


########################################
ShowPartnerStatus
Partner: ###.###.###
Host available:   Yes
Status available: Yes
My last change number:             3183271
Partner has seen my change number: 3183271
Partner is 0 changes behind.

Partner: ###.###.###
Host available:   Yes
Status available: Yes
My last change number:             3183271
Partner has seen my change number: 3183271
Partner is 0 changes behind.

########################################

VMDIR State
Directory Server State: Normal (3)

Environment

VMware vCenter 8.x

Cause

Inconsistencies in the VMDir replication topology or stale agreements encountered during the upgrade of multiple vCenter nodes in a shared SSO domain.

Resolution

1. Download the fix-psc script and upload to the vCenter
2. Run the fix-psc script with the rebuild parameter: ./fixpsc rebuild 

   ./fixpsc rebuild --healthy-psc-fqdn <Partner_vCenter_FQDN>

3. Restart all services: 

   service-control --stop --all && service-control --start --all

4. Verify replication status:

   /usr/lib/vmware-vmdir/bin/vdcrepadmin -f showpartnerstatus -h localhost -u administrator

5. Retry the upgrade once replication shows 0 changes behind.