VVF 9 Deployment Fails during Validation with error : "VC is in ELM mode"

Products

• VMware vSphere Foundation

Issue/Introduction

• The VVF 9 installer returns a specific error stating that the vCenter Server must not be in Enhanced Linked Mode to proceed.
• Manual inspection of the vSphere Client UI indicates a standalone environment, with no secondary vCenter instances visible in the inventory or linked mode management interface.

Environment

VMware vSphere Foundation 9.x

Cause

Although the UI showed a standalone vCenter, the VMware Directory Service (vmdir) database still contained stale replication agreements from a previously linked vCenter.

The hidden ELM state was confirmed by running the following commands on the vCenter Server Appliance:

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

These commands revealed a registered replication partner that was no longer active or visible in the UI.

Resolution

To resolve this issue, manually remove the stale replication agreement to split the Enhanced Linked Mode state. We need to manually split Enhanced Linked Mode by unregistering the stale replication partner from the vmdir database. Steps are below:

1. Take offline/powered-off snapshots of all nodes previously in linked mode to allow for a single point-in-time rollback.

2. Ensure the vCenter Server targeted for removal is completely powered off and has no active operations.

3. Log in to the surviving node (e.g., Node A) and decommission the stale node (e.g., Node B) from the SSO domain using this command:

    cmsso-util unregister --node-pnid Node_B_FQDN --username [email protected] --passwd 'your_password' 

4. After removing the stale partner and restarting vCenter, the ELM condition will be cleared, and the VVF 9 deployment will be proceeded successfully without errors.

    

Additional Information

Reference: Splitting Enhanced Linked Mode (ELM)