Migrate from VMware NSX for vSphere to NSX-T with Minimal Downtime

In order to help easily migrate from NSX for vSphere to NSX-T, with minimal downtime, the latest release of VMware NSX-T 3.0 introduces Maintenance Mode to NSX-T Migration Coordinator (a tool that has been built into NSX-T since the 2.4 release).  The Migration Coordinator tool is designed to run in-place on the same hardware that is running NSX for vSphere, and swap out NSX for vSphere bits with NSX-T.

This blog post is a follow up to the previous blog, Migration from VMware NSX for vSphere to NSX-T,  which covers Migration Coordinator. For more details on the Migration Process, please check out the previous blog.  This blog focuses on the Maintenance Mode feature which is part of the NSX-T 3.0 release.

What is Migration Coordinator?

Migration Coordinator is a tool that runs on NSX-T Manager. Its disabled by default since migrating from NSX for vSphere to NSX should only be a one-time task.

How to Enable Migration Coordinator

To enable Migration Coordinator, simply log in to NSX Manager via SSH and run the command “start service migration-coordinator”.

Enabling Migration Coordinator via SSH


Note: This command is also displayed when the Migrate page, which is under the System menu, is accessed on the NSX-T Data Center Manager UI.

Starting Service Migration Coordinator in NSX Manager


Once migration-coordinator starts up, the Migration Coordinator GUI is accessible via the NSX-T Data Center Manager GUI.  Click on System -> Migrate on NSX Data Center Manager GUI to show the Migration Coordinator GUI.

Service Migration Coordinator GUI in NSX Manager

Recap of the 5 Pre-Migration Steps

Before running the Migration Coordinator, the following five steps are necessary:

  1. Install NSX-T (Migration Coordinator is a tool built into NSX-T)
  2. Install NSX-T Edges (do not configure)
  3. Provide a TEP pool
  4. Create Compute Manager pointing to the vCenter connected to NSX-V
  5. Ensure NSX-V is in a stable healthy state with no pending changes since no changes are allowed during the migration phase

Once the above 5 steps are complete, you can proceed with the migration by clicking on “Getting Started” under “Migrate NSX for vSphere” on the Migrate page of NSX-T Data Center Manager GUI.

What is Maintenance Mode in Migration Coordinator?

With the 3.0 release of NSX-T, Migration Coordinator introduces Maintenance Mode. This mode reduces the down time of VMs, running during migration, comparable to what you would expect with vMotion. In maintenance mode:

  1. ESXi hosts are automatically placed in maintenance mode
  2. VMs on that host are automatically migrated out
  3. NSX for vSphere is replaced with NSX-T Data Center

How to Configure for Maintenance Mode

Migration Coordinator provides choices when configuring for maintenance mode.  First users can either opt into or out of maintenance mode.  If they opt into maintenance mode, they then have the choice of either an automated maintenance mode with zero user intervention, or a manual maintenance mode where users have to take action.  In this blog, we’ll focus on the automated maintenance mode.

Recap of Migration Coordinator Steps

Configuration for automated vs. manual maintenance mode can be found on the Resolve Configuration page. This is the second step of the Migration Process.  A quick recap for those unfamiliar:

  1. Import Configuration from the existing NSX for vSphere
  2. Resolve Configuration
    1. Interactively adjust any configuration related issues between NSX for vSphere and NSX-T Data Center Manager
  3. Migrate Configuration
  4. Migrate Edges
    1. At this point the edges installed in the Pre-Req steps are configured
  5. Migrate Hosts

For more details, please check out the previous blog on Migration Coordinator.

Automated vs. Manual Configuration

On the resolve page, we now have a new item “Choose Maintenance mode option for cluster” under “Maintenance Mode Options”.

Selecting Maintenance Mode For Cluster


Clicking on this item brings up a window where we can choose the appropriate maintenance on a per-cluster basis.  Or, we can simply accept the recommendations:


Choose Maintenance Mode on a Per-cluster Basis

Maintenance Mode Configuration

On the Hosts Configuration page, choose whether you would like to proceed with maintenance mode or to fall back to the previous non-maintenance mode setting.  Note that non-maintenance mode would mean replacing the VIBs, in-place, while the VMs are running on the host.  This will result in brief downtime while the VIBs are replaced.

To configure, click on Actions -> Change Migration Mode to choose either

  1. In-Place Mode (NSX is replaced while VMs are running on the host), or
  2. Maintenance Mode (VMs are first vMotioned out before replacing NSX on the host)
Configuring Maintenance Mode Within NSX-T

Maintenance Mode in Action

Once the Migration Coordinator starts off on a cluster, it will begin by placing a host in maintenance mode before replacing NSX for vSphere with NSX-T.  The GUI below shows the current status and details:

Status and Details of Migration Coordinator


The Tasks pane of vSphere will help track the actions taken by the Migration Coordinator, such as placing ESXi in maintenance mode and migrating the VMs out of that host etc.

Tracking Actions of Migration Coordinator with vSphere


NSX-T Migration Coordinator Demo with Maintenance Mode

Would you like to check out how this works?  Check out the 5 minute demo:

VMware NSX-T Technical Resources

Want to learn more?  Please check out the Migrate to NSX-T Resource Page or see below for additional resources.


Design Guides on NSX-T:

Try out NSX-T for free:

Other resources