NSX upgrade precheck failed with MP FQDN resolution check

Products

• VMware NSX

Issue/Introduction

• The following error message seen in UI.
  
  MP FQDN resolution check: [MP FQDN <NSX-Mgr-FQDN> is not resolvable on host <ESXi-host-FQDN>. Please ensure DNS is configured on host to resolve the MP FQDN.
  
  
• NSX Manager /var/log/upgrade-coodinator/upgrade-coodinator.log

Response of nslookup command 'nslookup <NSX-Mgr-FQDN> 2>&1 >/dev/null; echo $?' sent to host <host-uuid> : '1'
MP FQDN  <NSX Mgr FQDN> is not resolvable on host <ESXi-host-FQDN>, Please ensure DNS is configured on host to resolve the MP FQDN.

Environment

SDDC- 4.5 & 5.2

NSX- 4.2.x

Cause

ESXi using nslookup command to verify name resolution, if non-zero exit code returns, NSX Manager would mark FQDN check failure.

Resolution

1. Execute nslookup command in the reporting ESXi host shell:
   
   nslookup <NSX-Mgr-FQDN> 2>&1 >/dev/null; echo $?


2. If the return exit code is non-zero, run nslookup command directly:
   
   nslookup <NSX-Mgr-FQDN>


3. Check corresponding name resolution/DNS server to fix the issue.