Failed to expand a Stretched Cluster : Failed to validate host's network - Please make sure host management VLAN id and networkPoolId matches the specified fault domain.

Products

• VMware SDDC Manager

Issue/Introduction

• Unable to add additional ESXi Hosts in a AZ for a vSAN Strecthed Cluster.
  Description: Validate Expand Stretch Cluster ESXi Hosts(s) network 
Progress messages : Failed to validate host's network.
Remediation Message: Please make sure host management VLAN id and networkPoolId matches the specified fault domain.
  

Environment

• VCF 5.2

Cause

Renaming of the port groups was performed in vSphere.

Starting from VCF 5.2, Out of band changes are allowed to be made - "Out of Band Changes from vCenter: Out of Band changes from vCenter can be manually synced with SDDC Manager. This includes inventory changes (for example, adding a host to a cluster) and object name changes (for example, datacenter name, datastore name, port group name)."
VMware Cloud Foundation 5.2 Release Notes

This is supported on normal clusters but for a stretched cluster, we still need to follow the naming pattern of appending "az1_" and "az2_" for port groups in respective fault domains.

Resolution

• Rename the port groups back to prefix "az1_" for primary fault domain and  "az2_" for secondary fault domain.
• Renaming a VMware vSphere Distributed Switch and dvPortGroup is non-disruptive action.
• To rename a distributed switch port group:
  1. In vCenter Server, click Home > Inventory > Networking. 
  2. Right-click dvPortGroup and click Edit Settings.
  3. In the General section, change the name in the Name field.
  4. Click OK.