VCF Installer validation fails when converging a Two-Node vSAN Cluster hosting a vCenter Appliance

Products

• VMware SDDC Manager

Issue/Introduction

The VCF Installer validation fails during the converge operation when the vCenter Appliance is hosted on a two-node vSAN cluster.
The following errors are displayed:

･vSAN stretch cluster with VC VM doesn't have minimum 6 hosts in total with at least 3 hosts in respective fault domains
･Invalid cluster size present. vLCM vSAN storage cannot be used because cluster Cluster with size 2 is not supported, vLCM non-vSAN cluster Cluster has size 2 which is unsupported for CONVERT operation

Environment

VMware Cloud Foundation 9.0
VMware vSphere Foundation 9.0

Cause

Converging a two-node vSAN cluster that hosts its own vCenter Appliance is not supported. In VMware Cloud Foundation (VCF) and VMware vSphere Foundation (VVF), a two-node vSAN cluster is only supported in a Remote Office/Branch Office (ROBO) configuration. In this configuration, the vCenter Appliance must reside on a separate management cluster, not within the two-node vSAN cluster itself.

When using a two-node vSAN cluster, it must be integrated as a secondary cluster, with the vCenter Appliance residing on the primary (management) cluster. The two-node vSAN cluster is intended for workloads and must not host these management components.

･Supported configuration
vCenter
  -Datacenter
    -management vSAN cluster <======== Primary Cluster 
      -esx03.sample.com
      -esx04.sample.com
      -esx05.sample.com
       ･vcsa
    -two-node vSAN cluster   <======== Secondary Cluster
      -esx01.sample.com
      -esx02.sample.com
    -witness.sample.com

･Unsupported configuration
vCenter
 -Datacenter
    -two-node vSAN cluster
      -esx01.sample.com
      -esx02.sample.com
       ･vcsa
    -witness.sample.com

Resolution

If the vCenter Appliance must be hosted on a two-node vSAN cluster, the VCF Installer cannot be used.

Instead, follow the manual deployment method available for VMware vSphere Foundation (VVF):

1. Manual Cluster Setup: Configure the two-node vSAN cluster manually.

2. Standalone VCF Operations Deployment: With VVF, you can simply deploy the VCF Operations OVA as a standalone appliance without using the VCF Installer.

3. Registration: Manually register the appliance with your vCenter.

Note: This manual approach is only permitted for VMware vSphere Foundation (VVF) environments. It is not supported for VMware Cloud Foundation (VCF)

Additional Information

Two Node vSAN Deployments

Use Quickstart to Configure a vSAN Stretched Cluster or Two-Node vSAN Cluster

vSAN 2-Node Cluster Guide | Recommendations for vSAN, as a part of VMware Cloud Foundation 9.0

Converging Existing Virtual Infrastructure to a VCF or a vSphere Foundation Platform