In this blog I will explain what changes are need to allow a nested virtual machine to be powered on inside a virtual ESX host. This is something that I have been using to allow for study of the VCAP in a limited LAB situation.

The setup I have is physical ESXi 4.1 hosts on which I made a datacenter and cluster for LAB use. Inside this cluster I built 3 ESXi 4.1 hosts which have to be configured with the following disk configuration and OS selection:

• LSI Logic SAS
• Red Hat Enterprise Linux 6 (64bit)

Once the ESXi 4.1 hosts are built and everything else is configured the vmx file of each host needs to be edited. This will enable the virtual hosts to run virtual machines in the future. The lines that need to be added are as follows (I just added these lines to the end of the vmx file):

• monitor_control.restrict_backdoor = "true"
• monitor_control.vt32 = "true"

To add the above lines to the vmx file will require the file to be downloaded from the datastore and edited (for this I use Notepad++). The edited files are then uploaded back to the datastore (for good measure I remove the virtual machine and add it again to the inventory).

These additions will mean that nested virtual machines are now able to power on and the environment function like a physical one.

By Paul Wood