NSX-T Troubleshooting: Compute Manager Already Registered with Another NSX Manager

Apr 15, 2020 · 2 min read · NSX-T ·

After adding a compute manager, the Registration Status shows as Not Registered, and Connection Status is Down.

This is usually caused by a previously registered NSX-T Manager to vCenter, that has been deleted. If you remove the Compute Manager via the Delete option in NSX-T Manager, it also removes the registration from vCenter.

To fix it, the old NSX-T Manager registration needs to be removed from vCenter. Official doco here or follow along below.

Click on Not Registered to see the issue. Compute Manager sitea-vc.lab.vmw.one is already registered with other NSX Manager 172.31.150.14. Click the tick box and click Resolve.

If you get the following error, you'll need to remove the extension from vCenter as described in the next step.

As this Compute Manager is already registered with other NSX Manager, resolving this condition might impact the services to that NSX Manager. It is recommended to delete this Compute Manager from the other NSX Manager.

As mentioned above, this is because vCenter already has an NSX-T Manager registered with it, and vCenter can only have 1 NSX-T Manager registered to it. Although an NSX-T Manager can have multiple compute managers (vCenters) registered to it.

Resolution

In your web browser, go to https://yourVC.com/mob, and login with your administrator@vsphere account. In the Value column, click on content.

Then click ExtensionManager.

In the properties table, click (more...) to view the full list, then confirm the NSX-T extension has already been installed: extensionList["com.vmware.nsx.management.nsxt"].

If so, in the Methods tables, click UnregisterExtension.

Paste in the value com.vmware.nsx.management.nsxt, and Click Invoke Method. There's not much feedback, but you should see Method Invocation Result: void

Delete the compute manager in NSX-T Manager, and add vCenter as a compute manager again.

Good luck.