I used a different method of migration for a cluster that was migrating to a new vCenter Server on a new SSO domain. The destination vCenter Server was using the vDS so I had the same limitation as the previous migration. Though, I had a different idea for this one. I had enough resources in one of the clusters to first bring over half of hosts to the destination vCenter Server. Having this configuration made the process of live migrating my VMs easy by using the Cross vCenter Workload Migration Utility.

vMotion is not bound by a SSO domain and vMotion does not even know the concept of an SSO domain. I heard this discussed on the Virtually Speaking Podcast with William Lam describing his work on the Cross vCenter Workload Migration Utility. vMotion appears to only be within the same SSO domain because of the limitation in the GUI. However, there are APIs to migrate a VM to a different SSO domain. The utility is a technically a fling, but I see no problem with using it in a production environment.  After all, the APIs are there and the utility is just giving an easy to use interface.

Here’s the process I went though for this migration.

1. Export the vDS from the source vCenter Server
2. Import the vDS on the destination vCenter Server
3. Place host in maintenance mode
4. Document and then remove VMkernel ports
   1. Of course, migrate the management VMkernel to a standard port if it is on the vDS.
   2. VMkernel ports need to be removed before a host can be removed from a vDS.
5. Remove host from vDS
6. Disconnect host and then remove host from source vCenter Server
7. Add host to vCenter Server
8. Add host to vDS
9. Create and/or migrate  VMkernel ports that were previously deleted
10. Exit maintenance mode
11. Repeat steps 3-10 for additional hosts
12. Use the Cross vCenter Workload Migration Utility to vMotion VMs

Migrate Resources to a New vCenter Server (Part 1)
Migrate resources to a new vCenter Server – Methods for Migrations (Part 2)
Migrate resources to a new vCenter Server – Cross vCenter vMotion Utility (Part 3)
Migrate resources to a new vCenter Server – Unregister old vCenter Servers (Part 4)