This explains how to install ESXi into a VM. You will need ESXi 5.0 installed and have a copy of the ESXi 5.0 installation ISO.
Prepare ESXi 5 host
You will need to enabled hardware virtualisation on the ESXi 5 host. To do this connect to the ESXi 5 console and enter
echo ‘vhv.allow = “true”‘ >> /etc/vmware/config
You can verify this by viewing the “config” file
On the ESXi host create a new VM. Specify the guest OS version as Red Hat Enterprise Linux 5 (64-bit)
Make sure the NIC is set to E1000
Set the disk size accordingly and select finish.
You will need to change the hardware properties of the VM. Right click on the VM you just created and select “edit settings”. Make sure there is at least 2GB of RAM and 2x CPU
Then change the guest operating system type to ESXi 5.0
Click ok. You are now ready to install ESXi by connecting the CD to the ESXi 5.0 ISO.