I do not think that enough people are aware of this Fling, and that is really unfortunate.

First I want to take a step back and provide some history as to how this came about.  As most of you know, there is no easy way to live migrate a VM between different vCenter Servers that are not in Enhanced linked mode, which connects multiple vCenter Server systems together by using one or more Platform Services Controllers.

Some methods I have used in the past:

• Host migration to target vCenter Server:
  • Remove the managed ESXi host from the source vCenter and add it to the target vCenter and then perform a regular vMotion.  This method, however, comes with a lot of caveats for instance in order to remove the ESXi hosts all the ports groups needs to be on Standard Switches so this requires a migration from VDS to VSS. Additional information available here
• Enhanced linked mode
  • Setup enhanced linked mode between vCenter servers and perform a vMotion or Storage vMotion between the vCenter Servers, but this solution is not ideal when the source vCenter Server will get decommissioned. There is a way using supported workflows to remove ELM but is not supported by VMware so there is that! Good article by William about splitting vCenter Servers in ELM here.
• Hybrid Cloud Extention (HCX)
  • HCX is another option that I am very excited about trying in near future which provides vMotion, Bulk Migration, WAN optimization and automated VPN with Strong Encryption.  I have tested the tool for migration between on-prem and VMC on AWS and all I can say it is a game changer. Some more on that later in the year…

So getting back to why we are here!  With not having the ability to vMotion between 2 non-ELM vCenter Servers, William Lam took it upon himself to write a script using the vSphere API with PowerCLI that finally provides the sorely missed capability to vMotion a VM between 2 vCenter Servers that are in different domains! So naturally, the evolution of making the script easier to consume is to provide a nice looking GUI with a  fling!

Here you can find the Fling written by Vishal Gupta and William Lam. Props to both for all the time and effort to provide such a value-added feature.

Update 05.07.18:  

Version 2.0 has been released which brings some great new enhancements, especially the top 3 listed below.

• Added support to select individual host as the placement target
• Added support for migrating VMs with shared datastore
• Added clone functionality in addition to relocate
• Added resource summary details for placement targets
• Added a prompt to verify site thumbprint during SSL verification
• Added a link to refresh VM list in the inventory view
• Updated REST APIs to add operation type parameter

To run the fling you need => vCenter Server 6.0 and => Java Runtime 1.8.

To start the fling open a command prompt and type the following:

• # java -jar xvm-2.0.jar
  • this will start the fling on port 8080 on the localhost.
  • If you want to change the port because it is in use, add the following flag:
    • -Dserver.port=8800
• Connect to your localhost with port specified
  • http://localhost:8080
• 
• Select the Register tab and register to your source and target vCenters servers.
• 
• Select the Migration tab, provide information start the migration.
• Watch the magic happen…

Links:

• https://labs.vmware.com/flings/cross-vcenter-workload-migration-utility
• https://www.virtuallyghetto.com/2017/12/bulk-vm-migration-using-new-cross-vcenter-vmotion-utility-fling.html
• https://kb.vmware.com/s/article/1004775
• https://kb.vmware.com/s/article/2106952