Heads Up - ESXi 8.0 Host Client unable to attach existing virtual disk to VM

A couple of days ago, I had received an email from a customer that after upgrading to ESXi 8.0, they were no longer able to attach an existing virtual disk (VMDK) to a VM using the ESXi Host Client, which is accessible by opening a browser to the Hostname/IP Address of your ESXi host.

After selecting the desired VMDK to attach in ESXi Host Client wizard, the customer had noticed several fields were not populated as shown in the screenshot above and the workflow would not be allowed to complete as these fields are required.

Note: This issue also affects ESXi 7.0 Update 3i and potentially other newer releases, if they also contain the 2.x version of the ESXi Host Client. One workaround, which I have personally verified with ESXi 7.0 Update 3i is to uninstall the bundled esxi-ui VIB and install the prior version by downloading the ESXi offline depot (zip) for ESXi 7.0 Update 3g. While this may not be officially supported, for those that have a standalone ESXi host or using the Free ESXi version, this may be an acceptable workaround until a fix is available in a future patch/update. For detailed instructions, see my reply on this VMTN thread.

My use of the ESXi Host Client is typically limited because I have vCenter Server, but was curious about this issue since this is something I have done in the past using the ESXi Host Client without any issues. I saw the same behavior, which can easily be reproduced by creating a dummy VM with a virtual disk, detaching and attempt to re-attach the same VMDK.

I filed an internal bug and reached out to one of the ESXi Host Client Engineers and they confirmed that this is indeed a bug and they were able to quickly track down the problem relating to one of the Javascript calls which ESXi Host Client uses. This issue will be fixed in a future update of ESXi 8.x and currently only affects ESXi version that uses the new ESXi Host Client 2.x version, which was initially introduced with release of vSphere 8.

For customers that need a solution right now, you can use the following workaround by leveraging Automation. Below is an easy PowerCLI snippet that will allow you to attach an existing VMDK to VM by using the New-HardDisk cmdlet and connecting directly to ESXi host, since it also exposes a vSphere API.

The required parameters is a reference to a VM and the VMDK disk path which is in the format of "[datastore ] path/to/vmdk". While you can programmatically use PowerCLI and the vSphere API to construct this value. An easier way to retrieve this if you are only attaching a handful of VMs is by using the datastore browser within the ESXi Host Client. As you navigate to the desired VMDK, the disk path can be seen immediately below, which you can then copy and save that into the $diskPath variable.

$vm = Get-VM -Name "Test-VM"
$diskPath = "[sm-vsanDatastore] 25169063-0084-2e2d-a364-ac1f6b1a4efa/Test-VM_1.vmdk"
New-HardDisk -VM $vm -diskPath $diskPath -Confirm:$false

Below is an example output for running the PowerCLI snippet and now you have the desired VMDK attached to VM