vSphere services not starting and UI not working after modifying python packages or rpm packages in vCenter appliance

Products

• VMware vCenter Server

Issue/Introduction

vCenter services will not start after modifying either RPM packages or python packages in the vCenter appliance. 

This will present as vCenter UI unavailability

• "no healthy upstream" error observed through UI

Environment

vCenter 7.x/8.x/9.x

Cause

As per VMware Virtual Appliances and customizations to operating system and included packages any modification to Linux configurations on a VMware appliance will break the expected configurations value and cause service failures. 

Resolution

Revert a snapshot of the appliance or a backup of the appliance.