vSAN for File Services preventing ESXi upgrade between major versions

Products

• VMware vSAN

Issue/Introduction

When upgrading ESXi to a newer major version, for example from 7 to 8, vSAN for file services can prevent the upgrade due to built-in affinity rules.  

Environment

vSAN 7.x
vSAN 8.x
vSAN 9.x
ESXi 7.x
ESXi 8.x
ESXi 9.x
VCF 9.x
VCF 5.x

Cause

The existing vSAN for File Services nodes will not be able to migrate to the upgraded ESXi hosts the  leaving a cluster in a mixed mode with some hosts on the previous version and others on the new version.  

Resolution

Upgrade vSAN for File Services to the target version, for example, when upgrading from 7 to 8, vSAN for FS would need to be upgraded to 8.