VM in VM: QEMU, Xen, VMware ESXi and HyperV

I am trying to test some virtualization technologies. I don't want to install them on the real hardware directly. It is hard to change and maintain. So I want to install a VM in another VM. Following is a short summary:

----------------------------------Xen------------ Hyper-V--------- VMware ESX i
Underlying virtualization:
QEMU 0.10.5 -----------------\/--------------- X-------------------------- X
Virtual Box 3 ------------------?-----------------X-------------------------- X
VMware WS 6.5 --------------\/----------------?---------------------------- \/

It means Xen can run in a QEMU VM, but hyper-v and ESXi cannot run on current QEMU.

Develop GPL VMware ESXi drivers

http://open-vdrivers.wiki.sourceforge.net/Getting_Started

Install VMware ESXi in a VMware workstaion VM

http://wangchunhai.blog.51cto.com/225186/91400
http://wangchunhai.blog.51cto.com/225186/127783
http://wangchunhai.blog.51cto.com/225186/104710

Debugging Linux kernel with VMware

From vmware
http://stackframe.blogspot.com/2007/04/debugging-linux-kernels-with.html
From IDA pro
http://www.hex-rays.com/idapro/debugger/gdb_vmware_linux.pdf
GDB for windows:
http://www.redantigua.com/gdb-win.html

shrink vmware disk file by cloning harddisk

Ref:
shrink disk:
http://kegel.com/linux/jeos-vmware-player/jeos-vmware-player-howto.html
install grub:
http://ubuntuforums.org/showpost.php?p=117829&postcount=2

In summary:
1. install everything on VM1. Then remove unnecessary files.
2. add a second virtual disk.
3. boot from a liveCD,such as Ubuntu desktop 8.0.4
4. partition the second hard disk and copy files to it. (/mnt is the second hard disk)
fdisk /dev/sda (and type 'p' to print the partition table)
fdisk /dev/sdb (and use the n, t, and w commands to recreate the same table)
mkfs.ext3 /dev/sdb1
mount /dev/sdb1 /mnt
cd / (target)
ls egrep -v 'procsyslost.found' > /files.txt
cp -a `cat /files.txt` /mnt
5. Install grub (mbr) to be bootable:
1) Type "grub" in a console
2) Type "root (hd1,0)", or whatever your harddisk + boot partition numbers are (my /boot is at /dev/sdb1, which translates to hd1,0 for grub).
3) Type "setup (hd1)", or whatever your harddisk No. is.
4) Quit grub by typing "quit".
6. shutdown VM. remove the first hard disk.
7. boot.

shrink vmware disk file

http://www.howtoforge.com/how-to-shrink-vmware-virtual-disk-files-vmdk

build vmware tools for Ubuntu guest

sudo apt-get install build-essential

sudo apt-get install linux-headers-$(uname -r)

reference:
http://blogs.tech-recipes.com/johnny/2006/09/05/installing-vmware-tools-for-ubuntu-linux/