Virtualization 101

Posted by on October 23, 2007 under Uncategorized |

This page is under construction, but to get you started, here is my 2 cents thus far:

There are a few major technologies in the Virtualization (on Linux) world. VMWare, Xen, and KVM (and KQemu, Qemu).

The long/ short of it - you’ll want to end up on KVM, but will probably use VMWare Server in the short term.

 

VMWare - the VMWare Server for Linux works well enough and is freely available, but with licensing restrictions. It is nicely compatible with images created on Windows hosts.

Xen - I thought this was the way to go, but then Citrix stepped in (red flag). Now, with KVM a part of the Kernel, I wouldn’t recommend it.

KVM - This is fairly new, but the technology is going to grow over time. The advantage KVM has is that it is a part of the mainline Linux Kernel. It is based off of the QEMU project (which is excellent for testing, but painfully slow in practice). KVM basically takes QEMU into the Kernel (yes, KQEMU can also be used). It is compatible with VMWare Server created VMDK disks. It requires IntelVT or AMD-VT? (Virtualization) support on your processor.
Synopsis:
If you have a computer that supports the Virtualization extensions, KVM is where you want to go. If not, you can use QEMU, and migrate to KVM when you get a new system.

However, I have found (thus far) that KVM/ QEMU are a pain in the @ss to get working correctly. On the other hand, VMWare Server is rather simple (by comparison) once it is installed.

In truth, I am currently using VMWare Server only. But I have been testing QEMU and KVM for sometime. I have been converting my VMWare systems from 2GB split SCSI files, to single IDE files - these are compatible with KVM/ QEMU

UPDATE (10/24):

So, I have finally made SOME progress with KVM.  I am running Ubuntu 7.10 desktop (Gutsy Gibbon) with KVM installed (downloaded from source KVM-48 and compiled per instructions - I got some errors, but it worked).  I was able to install Zenwalk desktop, using KVM (instead of QEMU).

What did I learn?  It appears that the issue I was having was specific to the Ubuntu installer!  Not the host, but guest.  I was running Ubuntu as my host system, and installing Ubuntu into a KVM guest, but it would fail on boot from the CD image.  There is a change you can make to the boot commandline (blacklist something or other..) that will allow the installer to boot.  But, after installation is compelte, the system beings booting, and then drops you to some alternate Debian command line.  I read something about a VGA problem with the Ubuntu bootloader… I don’t know.  All I know is that when trying to install Zenwalk as a guest, it worked fine.  I’ll next try with XP, and I am sure that will work OK too.