The Goal

A vSphere administrator may need to set an ESXI Host into maintenance mode for any number of reasons, however, when using VMware’s Horizon View additional steps may need to be taken.

The Problem

When using Instant Clones, simply setting a host into maintenance mode will eventually time-out and fail as the CP-Parent / CP-Template / CP-Replica Infrastructure virtual machines will not migrate to another host. While the vCenter environment knows the host must be vacated in order to be placed into maintenance mode, the Horizon View infrastructure still believes the host may be used for provisioning.

The Fix

The attribute that must be modified is the InstantClone.Maintenance found under the ‘Custom Attributes’ tab on the ESXI host found within the vSphere console.

Simply select ‘Edit’ on the Custom Attributes tab and set the value of InstantClone.Maintenance to 1. 

After setting and saving the new value, the CP-Parents / CP-Templates / CP-Replicas will begin to be deleted. These virtual machines will be re-created once the host is allowed to be utilized by the environment again.

Wait for about 5 minutes and you’ll notice that the Attribute will change from 1 to 2. Once the Attribute has automatically changed to 2, the Horizon infrastructure virtual machines have been removed and the host may now be set into maintenance mode.

For More Information:

If you want to know more about this process, or simply want to hear from VMware themselves, check out the following knowledge base article outlining the above steps: Entering and exiting maintenance mode for an ESXi host that has Horizon instant clones (2144808) (vmware.com)