After you have started the migration process, you can roll back the migration to undo some or all your progress. You can also cancel the migration, which removes all migration state.

You can roll back or undo the migration from some of the migration steps. After the migration has started, you can click Rollback on the furthest step completed. The button is disabled on all other pages.

Table 1. Rolling Back NSX Data Center for vSphere with vRealize Automation Migration
Migration Step Roll Back Details
Import Configuration Click Rollback on this page to roll back the Import Configuration step.
Resolve Configuration Rollback is not available here. Click Rollback from the Import Configuration page.
Migrate Configuration Click Rollback on this page to undo or remove the migrated configurations in NSX-T. The inputs provided on the Resolve Configuration page are removed. The migration log files are removed from the NSX Manager appliance. You must start a new migration.

Before rolling back the migration from the Migrate Configuration page, it is recommended to collect the Support Bundle. For more information, see Collect Support Bundles in the NSX-T Data Center Administration Guide.

Verify that the rollback was successful before you start a new migration. Log into the NSX Manager web interface and switch to Manager mode. Verify that all configurations have been removed. For more information about Manager mode, see Overview of the NSX Manager in the NSX-T Data Center Administration Guide.

Check Realization Click Rollback on this page to undo this step and return to the Migrate Configuration page. The migrated configurations in NSX-T are retained.
Migrate Edges Click Rollback on this page to roll back the migration of Edge routing and services to NSX-T.
Caution: If you roll back the Migrate Edges step, verify that the traffic is going back through the NSX-v Edge Services Gateways. You might need to take manual action to assist the rollback.
Migrate Hosts

Migration coordinator does not provide a rollback in this step. However, you can still do a manual rollback to remove NSX-T from the migrated hosts and reinstall NSX-v on the hosts.

If you are migrating from NSX-v 6.4.8 or later, run the following REST API on the NSX-v NSX Manager before doing the manual rollback, and then reinstall NSX-v on the hosts.

POST api/2.0/nwfabric/blockEamEvents?action=unblock

This API enables the vSphere ESX Agent Manager (EAM) on the hosts so that the NSX-v VIBs can be installed correctly.

If you are migrating from NSX-v 6.4.4, 6.4.5, or 6.4.6, this API is not needed.

Note: It is better to do a manual rollback of a failed host after the cluster, which contains the failed host, has stopped. If you are doing an In-Place host migration, and chosen parallel migration order within the cluster, then wait until the migration of all hosts in the cluster stops, regardless of failure or success. If you have chosen serial migration order of hosts within the cluster, migration stops when a host migration fails.

When you roll back a migrated configuration that contains Network Introspection redirection rules, you might see the following error message:

Service Insertion failed with '400: The object path=[/infra/segments/service-segments/vdnscope-1] 
cannot be deleted as either it has children or it is being referenced by other objects path=

This error occurs because a service segment in NSX-T depends on a service chain. A service chain is not deleted until all the redirection rules referenced by it are deleted. Wait for approximately five minutes and try rolling back the migrated configuration again.

There is a Cancel button on every page of the migration. Canceling a migration deletes all migration state from the system. The migration coordinator shows the following warning message when you cancel a migration at any step:

Canceling the migration will reset the migration coordinator. It is advisable to rollback this 
step first or it might leave the system in a partially migrated state. Do you want to continue?
Caution: Do not cancel a migration if Edge or Host migration has started. Canceling the migration deletes all migration state and prevents you from rolling back the migration or viewing past progress. If needed, roll back first to a point before Edge migration has occurred, and then cancel.

Canceling a migration might leave the system in a partially migrated state with some stale configuration. However, the migration log file is still retained on the NSX Manager appliance, but the deployment configuration file is removed. You must upload the deployment configuration file again on the Import Configuration page and start a new migration.

Scenario: Cancel Migration

Typically, you should cancel a migration when rollback and everything else fail.

For example, assume that on the Migrate Configuration page, the migration coordinator displays an error while migrating the configurations of some objects to NSX-T Data Center. However, some object configurations are migrated successfully to NSX-T. You can roll back the migration.
  • If the rollback succeeds, the NSX-v object configurations that are migrated successfully to NSX-T Data Center are undone or rolled back. All the inputs that you provided on the Resolve Configuration page are removed. You must start a new migration again.
  • If the rollback fails, you can cancel the migration. The migration state of the migration coordinator is reset. Migration coordinator considers that there is no pending migration, and the migration state is deleted. However, the object configurations that are migrated successfully to the NSX-T environment remains. You can use any one of these two approaches:

    Approach 1: Manually remove the stale migrated configurations from NSX-T, and start a new migration. By removing the stale configurations, you can avoid potential conflicts during a new migration.

    Approach 2:
    1. Delete the current NSX Manager appliance.
    2. Deploy a new NSX-T environment with NSX Manager and NSX Edge appliances.
    3. Start a new migration.