vCenter upgrade through SDDC manager fails with error message "Upgrade failed: Precheck VC services failed during pre-validation"

Products

• VMware vCenter Server

Issue/Introduction

vCenter upgrade through SDDC manager fails with error message "Upgrade failed: Precheck VC services failed during pre-validation"

Same error reported in /var/log/vmware/vcf/lcm/lcm-debug.log 

Environment

SDDC Manager 4.x

vCenter 7.x

Cause

One or more required services for the upgrade are down on vCenter; failing the pre-validation from SDDC Manager

Resolution

1. Using the VDT Tool from KB 344917 - identify in the report which services are down on the culprit vCenter
2. Start the highlighted services with below command:
   • service-control --start <service-name>
3. Once VDT Tool no longer reports that certain services should be started - retry upgrade from SDDC Manager