NSX-T 3.1.3.6 - Upgrade coordinator, compatibility issue to upgrade to NSX-T 3.2.0.1

Issue

Today, during the upgrade of NSX-T Data Center infrastructure from 3.1.3.6 version to 3.2.0.1 I faced out the following issue.

Verifying that everything was correctly in the compatibility matrix, loaded the .mub file I received the following error:

New NSX Upgrade version is not compatible with current NSX version, you cannot upgrade to this version

Solution

Logged into the NSX Manager CLI as root user I checked the upgrade coordinator log files /var/log/upgrade-coordinator/upgrade-coordinator.log, then I noticed the ERROR line:

Error while calling uc_helper for verification of Upgrade bundle VMware-NSX-upgrade-bundle-3.2.0.1.0.19232396.mub. See uc_helper logs

Since the log file of the uc_helper was not present in the appliance manager, I did a google search and found the KB87835 "NSX-T Manager upgrade blocked by Backup passphrase precheck (87835)"

I followed the workaround described into the KB that consist to perform next steps:

• Download the correct uc_helper file attached to the KB. In my case 3x_to_3201_uc_helper
  
• From the NSX-T UI, identify which Manager is orchestrating the upgrade.
  The upgrade UI page is only active on one Manager and this is the orchestrator node.
  
• Copy the downloaded 3x_to_3201_uc_helper.py file to /image directory on the orchestrator NSX Manager node.
  
• ssh to the orchestrator node as root user.
  If root access is not allowed, ssh as admin and switch to root user with the "st en" command followed by the root user password
  
• Backup the file
  cp /opt/vmware/upgrade-coordinator-tomcat/bin/uc_helper.py /opt/vmware/upgrade-coordinator-tomcat/bin/uc_helper.py.bak
  
• Perform remediation
  cat /image/3x_to_3201_uc_helper.py > /opt/vmware/upgrade-coordinator-tomcat/bin/uc_helper.py
  
• From the NSX-T UI, retry to upload the upgrade .mub file .... and wait.
  

Now the Bundle file has been loaded successfully and we can continue with the UPGRADE.

That's it.