NSX upgrade requires healthy communication with NAPP.
VMware NSX 4.x
Errors similar to following messages will be reported in upgrade-coordinator.log
2024-10-08T15:30:24.237Z INFO http-nio-127.0.0.1-7442-exec-2 UpgradeQueryServiceImpl 1780227 SYSTEM [nsx@6876 comp="nsx-manager" level="INFO" subcomp="upgrade-coordinator"] Returning upgrade status summary for EDGE details as Pre-upgrade checks failed for EDGE: Failed to execute Check for NSX Application Platform version for upgrade. [UC] Error in rest call. url= /napp/api/v1/platform/monitor/platform/status , method= GET , response= no healthy upstream , error= SERVICE_UNAVAILABLE:no healthy upstream ..
Within NSX T UI the option "Start Upgrade" can not be selected
In the event when NAPP environment is not healthy, NSX upgrade will not proceed and the upgrade will fail.
After fixing NAPP issues, proceed to NSX T upgrade.