When NSX Upgrade is done via API, the upgrade pre-checks fail with error

Products

• VMware NSX

Issue/Introduction

• NSX is being upgraded via API
• After the PUB file is uploaded, a pre-check API is initiated and it fails with error
  Pre-upgrade checks failed for HOST: Failed to execute ESXi in-place upgrade dataplane check.

Environment

VMware NSX

Cause

The upgrade-coordinator is not upgraded after the PUB is uploaded. As upgrade via API step-by-step process is not documented, users may not invoke the UC upgrade API before the other upgrade tasks are run.

Resolution

This is an user error.

Workaround:
The upgrade coordinator must be upgraded before the prechecks can be run. 

These are the steps that follows a .pub upload when PUB is uploaded via the UI. 
Validating Bundle
Uploading Bundle
Extracting Bundle Signature
Verifying Bundle Signature
Checking Version Compatibility
Processing Bundle
Deleting Temporary Files
Upload Complete
Upgrading Upgrade Coordinator -> after the upload
Extracting Upgrade Bundle
Loading Metadata
Reloading Upgrade Coordinator
Synchronising Repository
Upgrading Upgrade Coordinator on Other Nodes
Upgrade Coordinator Upgraded on all Nodes

UC can be upgraded by either of these methods.
"POST /api/v1/upgrade?action=upgrade_uc"

or upload the PUB with 'install' set to true.
"POST /api/v1/upgrade/bundles?action=upload&install=true"