"Your environment is now in mixed mode. It is recommended you update your linked vCenter Servers to the same version" warning banner in vSphere Client due to vmdir inconsistencies

Products

• VMware vCenter Server

Issue/Introduction

• vCenters in Enhanced Linked Mode display the following warning banner in the vSphere Client:
  "Your environment is now in mixed mode. It is recommended you update your linked vCenter Servers"
• When checking the Replication status on both nodes with the command below, no output is returned:

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

• • This means that there is no replication agreement between the nodes, even though they are in Enhanced Linked mode.
• vCenter System Configuration shows the vCenter Servers are on the same version.
  • Additionally, the vCenters show "No replication partner":

• The vCenters were recently upgraded from 7.x to 8.x.

Environment

vCenter 7.x, 8.x

Cause

The lack of a replication agreement between the nodes already in Linked mode, results in VMDIR being inconsistent. Without a replication agreement, the 'partner' node has no way of keeping track of any changes on the node that is supposed to be a partner.

• This resulted in the 'Mixed mode' banner appearing after both vCenters were upgraded from 7.x to 8.x.

Resolution

Follow KB: Fixing VMDIR inconsistencies with SSO domain repoints to repoint the vCenters to a new SSO domain.

Note: FixPSC will not resolve the issue since there isn't a replication agreement between the nodes, despite the vCenters already being in ELM.