NSX upgrade pre check fails for host UNKNOWN

Products

• VMware NSX

Issue/Introduction

• During the NSX upgrade process, host pre-checks may display a warning indicating that one or more hosts are unknown.
• The hosts host1.example.com and host2.example.com were previously listed in the inventory and prepared for NSX but have since been removed from vCenter and unprepared.
• A typical error message observed during the Pre-Upgrade check for a specific host may resemble the following
  Pre-upgrade checks failed for HOST: [UC] Error in rest call. url= /nsxapi/api/v1/transport-nodes/####-####-####-####-########/status , method= GET , response= { "httpStatus" : "NOT_FOUND", "error_code" : 29501, "module_name" : "HeatMap", "error_message" : "Transport node ####-####-####-####-######## not found" } , error= 404 : "{<EOL> "httpStatus" : "NOT_FOUND",<EOL> "error_code" : 29501,<EOL> "module_name" : "HeatMap",<EOL> "error_message" : "Transport node ####-####-####-####-######## not found"<EOL>}

Environment

VMware NSX
VMware NSX-T

Cause

The ESXi host was migrated to a different vCenter, which is managed by another NSX-T Manager.

Resolution

1. Put the ESXi into maintenance mode. Refer Enter and Exit Maintenance Mode with ESXCLI
2. Uninstall NSX from a Managed Host in a vSphere Cluster. Refer Uninstall NSX from a Managed Host in a vSphere Cluster