Workaround for when you cannot vMotion live VMs to new host (but powered off migration works) because the vMotion vmk's are in different subnets.

Products

• VMware vSphere ESXi

Issue/Introduction

When attempting to vMotion VMs from one ESXi to another and the vMotion vmk's are not configured in the same subnet, and the vMotion fails.
Additionally, you have the ability to migrate the VM while the VM is powered off.

Cause

In this scenario, the vMotion vmk's being configured in different subnets would need to have routed connections (per ESXi Host), which it does not have, and is the reason it will not connect to perform the vMotion using the vMotion vmk. The Management vmk during installation has a default gateway (router) configured and will provide a connection between different subnets on the ESXi Hosts.

Resolution

To work around this, record all of the vMotion vmk IP settings involved and remove the vMotion vmk from all source and destination hosts involved. Edit the Management vmk and add the vMotion service (check the vMotion checkbox).

NOTE: THIS IS A WORKAROUND ONLY, this setup is not a design recommendation as this goes against best practice, which is to have a different subnet and vmk per service (IE: vMotion, vSAN, Fault Tolerance, Management etc...)

For additional information please see:

How to Place vSphere vMotion Traffic on the vMotion TCP/IP Stack of Your ESXi Host

What Are the vSphere vMotion Networking Requirements

vSphere Networking Best Practices