vCenter Server upgrade stuck on 80% of RPM installation

Products

• VMware vCenter Server

Issue/Introduction

• The upgrade process is stuck on 80% the RPM installation of installer with below messages:
  
  Upgrade - Stage 1: Deploy vCenter Server
Waiting for RPM installation to start. This may take several minutes.
  
  
• The VAMI of the new, aka destination vCenter Server can be accessed successfully with the message prompt:
  
  vCenter Server 8.0 has been successfully installed. However, additional steps must be completed before it is available for use. Click one of the links below to continue setup.

Environment

VMware vCenter Server 8.0.x

Cause

The installer of vCenter Server can not get the status update of upgrade process in the new vCenter Server due to somethings liking network interruption. 

Resolution

1. The installer progress stuck on RPM installation can be ignored. 
2. The upgrade process can be continuous via VAMI by selecting the option of Upgrade. Following the steps of upgrade process in Quick guide to upgrade from vCenter Server 7.0 to 8.0