Sometimes instant clone VDI gets stuck in customizing state during image push. It shows Boot Manager screen (EFI diagnostics).

Products

• VMware
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• ModeB is selected as the provisioning scheme for the instant clone pool.
• When opening the affected VDI in the vSphere Client console, Boot Manager screen (EFI diagnostics) is displayed.
• The issue sometimes occur only in some unspecified VDIs.
• You can see errors similar to the below in Connection Server's debug log:Location of Horizon View log files (1027744)
  [EventLogger] Error_Event:[BROKER_PROVISIONING_ERROR_VM_CUSTOMIZATION_TIMEOUT] "Provisioning error occurred for Machine VDI-1: Customization operation timed out": MachineId=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, MachineName=vdi-1, Node=cs.test.local, Severity=ERROR, Time=Mon Jan 01 01:00:00 JST 2024, Module=Broker, Source=com.vmware.vdi.desktoptracker.VmInformation, Acknowledged=true

Environment

VMware Horizon 8
VMware vSphere 7.0.x

Cause

An issue has been reported in vSphere 7 where the bootloader EFI firmware file may occasionally be missing during the boot sequence of link clone virtual machine.
Horizon Instant Clone VDI (ModeB) is created as a link clone VM that references the vmdk of the replica VM. As such, it may be affected by the above issue.

Resolution

VMware is aware of this issue and working to fix it in a future release.

Workaround:
As a possible workaround, configure virtual machine options as bellow:

1. From the vSphere Client, right-click the master VM and go to Edit Settings.
2. Open VM Options tab, 
3. Configure as below under Boot Options section.
   Boot Delay: 3000 milliseconds
   Failed Boot Recovery: Checked
      If the VM fails to find boot device, automatically retry after: leave as default value (10 seconds)
4. Crate a new snapshot with the configurations above.
5. On affected Horizon pool, run the image push using the snapshot above.