NSX-T 3.0 – VMkernel Migration to an N-VDS Switch

Most of the customers are moving to NSX-T environment. One common use case / questions would have been, what happens to existing VMkernel Adaptors OR how does the migration of VMkernel works in NSX-T. One of my recent customer had similar use case, wherein he had backup application running in the VMware vSphere environment which had 2 vmk’s and the plan was to migrate all networks in to NSX-T (Overlay or VLAN). There are ‘n’ number of things to consider before we plan for such migrations. First, we got the email confirmation from the application vendor on application compatibility with NSX-T. It was also important to get confirmation from the vendor if the backup application will still behave as expected and will be able to backup VM’s connected to Overlay Segments.


Note: Some 3rd party applications do not support or understand Opaque networks. (For vCenter, all networks that have been created in NSX are Opaque networks)


In my case, customer had to upgrade the backup application to vendor suggested version to make it compatible with NSX-T and to be able to backup VM’s connected to NSX-T (Overlay & VLAN) networks.


Some additional points…
Please keep in mind that we are talking about 3rd party application vmkernel adaptors and NOT vMotion, management or vsan vmk’s. The migration process will always not be the way it is mentioned in this article. It completely depends on customers env and at what point you are planning for this migration and for which vmk’s. Shared Compute, Edge & Management cluster with only 2 pics and not on vSphere 7.0 version will need proper planning and migration methodology. Greenfield env will give you flexibility to migrate vmkernel using network mapping while configuring hosts transport nodes, whereas brownfield env will eat your head. So plan and prepare wisely before you propose your plan to the customer.

Following is my lab setup for this post.
NSX-T 3.0 installed and configured.
Four hosts cluster prepared and configured for NSX-T. It is a shared cluster for all components.
Physical Adaptors – vmnic0, vmnic1 connected to vDS on vCenter. And vmnic2, vmnic3 connected to nvds in nsx-t.
BGP routing is in place.
Edge VM’s uplinks have been configured and connected to logical segments.
Port group name ‘vDS-Test-1650’ with vlan id 1650 is in place. This port group has VMkernel Adaptor 3 (vmk3) and it has been configured on all hosts in the cluster.
‘Test-10’ VM connected to ‘vDS-Test-1650’ for testing connectivity.

Here is the plan.
Create vlan based logical segment in nsx-t for 1650 network.(VLAN-1650 LS)
Move ‘Test-10’ VM from ‘vDS-Test-1650’ port group to ‘VLAN-1650 LS’ logical segment.
Migrate vmkernel adaptor 3 (vmk3) from port group to logical segment.
Test connectivity from test vm to vmk ip after migration.
Revert the configuration.

With that lets get started…

‘vDS-Test-1650’ port group on distributed switch.

‘Test-10’ VM connected to ‘vDS-Test-1650’

Verify the connectivity to ‘172.16.31.110’ (DC in my env) from Test-10 VM.

ESXi01 has vmk3 created with network label as vDS-Test-1650 port group.

Similar configuration on other hosts.


Time to create vlan based logical segment in nsx-t.
Log into NSX-T VIP> Networking> Segments> Add Segment
Name: VLAN-1650
TZ: Shared VLAN TZ
VLAN: 1650

VLAN based logical segment is ready to move the VM’s into it.
Test-10 VM> Edit Settings> Change the network to newly create logical segment.

Test-10 VM now sits on VLAN based logical segment in NSX-T. Test the connectivity to DC again.

Let’s move vmkernel from vCenter PG to NSX-T LS.
System> Fabric> Nodes> Host TN> Select 1st esxi and click on Action> ‘Migrate ESX VMkernel and Physical Adapters’

Select appropriate N-VDS to migrate to
Select the VMkernel Adaptor that you plan to migrate in to NSX-T.

And then the destination Logical switch that we created earlier.

Next > Select physical adaptors in N-VDS
Note: These vmnics have already been assigned to N-VDS and not the new ones.

Select physical nics and appropriate uplinks and SAVE.

You get a warning at this stage. Continue.

Once it is successful, verify it on the vCenter.
Notice that the vmk3 is sitting on the “data-nvds” instead of “DATA-VDS”

Testing connectivity to vmkernel (172.16.50.101) adaptor from the VM.

All Good. We have successfully migrated VMkernel (vmk3) to nsx-t. There may be situations where you want to revert back the configuration if expected results fails after vmk migration. I will cover the reverse migration in my next blog.

I hope that the blog has valuable information. See you all in next post.

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