VSAN cluster experiences a network partition when enabling the vSAN tag on a VMkernel adapter configured on a distributed switch

Products

• VMware vSAN

Issue/Introduction

Symptoms : 

• The vSAN Skyline Health reports a cluster partition immediately after the vSAN tag is enabled on a VMkernel adapter configured on a distributed switch.
  
  
  
• Enabling the vSAN tag on vmkernel adapter configured on standard switch resolves the network partition issue.

Environment

• VMware vSAN 7.x
• VMware vSAN 8.x

Cause

The uplinks (physical adapters) are not configured on the distributed switch.

Cause validation:

• Log in to vCenter and navigate to the affected host. Under Configure > Virtual Switches, verify that no uplinks (physical adapters/NICs) are assigned to the distributed switch.
  
• Log in to the affected host via SSH and run the command esxcfg-vswitch -l to confirm that the distributed switch has no uplinks configured.
  esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
##########         2520        1           128             1500

Resolution

• Add the appropriate uplinks (physical adapters) to the distributed switch.
  OR
• Migrate one or more unused uplinks to the distributed switch and then enable the vSAN tag on the VMkernel adapter configured on the distributed switch.
  Refer : How to manually migrate a NIC (vmnic) from a Standard Switch to a Distributed Switch for a single ESXi host