NSX-T failed to upgrade to 3.2.1.1 due to NAT rule data-migration failure

Products

• VMware NSX

Issue/Introduction

Symptoms:

• Attempting to upgrade from NSX-T 3.1.x to NSX-T 3.2.1.1 fails
• Entries similar to the below are observed in the NSX Manager support bundle in /var/log/proton/data-migration.log:

2023-01-11T10:33:15.966Z WARN main NatMigrationTask 4047 - [nsx@6876 comp="nsx-manager" level="WARNING" subcomp="manager"] NatSection: unexpected error in migrating table
java.lang.NullPointerException: null


2023-01-11T10:33:15.968Z WARN main UfoCorfuTableMigrator 4047 - [nsx@6876 comp="nsx-manager" level="WARNING" subcomp="manager"] ERROR while running custom migration MappingDetails{modelName='com.vmware.nsx.management.edge.nat.model.NatRule', migrationType=CUSTOM_MIGRATION, reason='null', customMigratorClassName='com.vmware.nsx.management.migration.task.edge.nat.NatMigrationTask', fieldMappings=null, targetProtoName='null', requiresCustomCode='false', owner='null', apiToTest='api/v1/logical-routers/<logical-router-id>/nat/rules'}

Environment

VMware NSX-T Data Center
VMware NSX-T
VMware NSX-T Data Center 3.x

Cause

The Null Pointer Exception is caused when the Logical-Router is null. 
NAT attempts to retrieve the Logical-Router entry by logicalRouterId but the Logical-Router returns as null.

Resolution

To resolve this issue please upgrade to 3.2.1.2.

Workaround:
There is no workaround for this issue.