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Nested ESXi installation using HTTPS boot over VirtualEFI in vSphere 8

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In vSphere 7.0 Update 2, an enhancement was made to the Virtual Machine's UEFI firmware called VirtualEFI that would enable ESXi to run in a VM (Nested ESXi) and perform an HTTP Boot given the ESXi bootloader URL without requiring any traditional PXE infrastructure.

This was especially useful for anyone testing or developing ESXi automation for use with ESXi Kickstart, where you can quickly prototype your automation without additional infrastructure dependencies and once the automation has been vetted, you can then leverage that exact same automation in your physical ESXi provisioning infrastructure.

The original solution had only supported HTTP and I recently came to learn that we can now also support HTTPS in vSphere 8!

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How to recover ESXi installed on USB device after disabling vmkusb module?

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I have to say, this is one of the more interesting challenges that I have come across in quite some time. A user was looking for assistance after they accidentally disabled the vmkusb module, which is the USB driver for ESXi and allows it to communicate with USB devices that are connected to the system.

The vmkusb module also plays a very critical role if you have ESXi installed on a USB device, as the driver is required for proper functionality such as being able to save the ESXi state and configurations to the USB device. So what happens when you disable the vmkusb module and you reboot the ESXi host, which is also installed on a USB device?

Well, everything continues to work including VMs since ESXi by design runs in memory after the initial boot from the USB device. However, any configuration changes made after that is lost after a system reboot including the attempt to re-enable the vmkusb module since ESXi is unable save any of the settings to the USB device. Fortunately, I was able to help the user out as I had a few ideas on how we could fully recover from this type of scenario and hence the blog post.

Hopefully a lesson can be learned here, do not make changes or disable things that you are not familiar with 🙂

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ACPI motherboard layout requires EFI - Considerations for switching VM firmware in vSphere 8 

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One of the important settings to consider when creating a new Virtual Machine in vSphere is the VM firmware, which can either be BIOS or EFI and can be configured under VM Options->Boot Options->Firmware. After selecting the desired guest operating system (GOS) in vSphere, the system will default to a recommended firmware type and can also be overridden by the user. Ultimately, the selection of the VM firmware should be determined by what your GOS supports.

If you ever need to change the VM firmware, you typically will need to re-install the GOS because it does not understand the new firmware change (just like in a physical server) and more than likely the GOS will also not boot due to this change and this is the existing behavior from GOS point of view.

For a net new VM creation, prior to vSphere 8, if you had configured a VM using EFI firmware and you have not installed a GOS and realized that you had made a mistake and needed to change the VM firmware to BIOS, you could easily do so using the vSphere UI or API and then install your OS. In vSphere 8 and specifically when using the latest Virtual Machine Compatibility (vHW20), you can not just switch the VM firmware after the initial VM creation, especially if you had started with EFI firmware and wish to change it to BIOS.

In doing so, you will come across the following error message:

ACPI motherboard layout requires EFI. Failed to start the virtual machine. Module DevicePowerOnEarly power on failed.

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