Since this procedure can usually be easily accomplished by using the vSphere Web Client, I'd advise to use that solution - however, if the Web Client is not installed, this nested virtualization-setup can be enabled by using the vSphere Client:


    1. Connect to your ESXi host, install a Linux system to it (in my case it was an Ubuntu 14.04 LTS running on an ESXi 5.5 host);
    2. Install the available updates (and Qemu/KVM/Libvirt/Virt Manager) as usual;
    3. Edit the host system configuration file: browse the ESXi host datastore for the Linux installation folder and locate a .vmx file, download it to your local computer and add vhv.allow = TRUE as the last line, save the file and upload it back to the datastore.