I really liked VirtualBox and got a lot of use out of it when running my old Windows XP system under Ubuntu. However, the lack of support for 64-bit systems proved too problematic. In testing Ubuntu 8.04 (Hardy Heron) I was only interested in testing the 64-bit versions as that was all I would be running. As some bugs are architecture dependent (iproute and monsterz come to mind) it's important to perform testing on the architecture you will actually use. Under Ubuntu 7.10 (Gutsy Gibbon) I had some issues with QEMU and KVM though I was able to use them enough to do testing (though often only through QEMU with specific parameters at a less than ideal speed). However in Ubuntu 8.04 I found both applications improved and decided to search for a nice front-end to replace the functionality I was used to with VirtualBox.

In an effort to help with testing the beta release of Ubuntu 8.04 I wanted to set up a number of virtual machines running the OS so I could perform various tests, such as whether certain but in Ubuntu 7.10 (Gutsy Gibbon) had been fixed. Unfortunately I have not been successful so far. As every system save 1 is running the amd64 architecture that is the architecture I would prefer to test. However, it seems that trying to have a virtual amd64 guest on an amd64 host using open source software is problematic.

I just did some reading on unkillable processes. I've seen this happen a few times before and wondered what caused it. I experienced it again today when using KVM. Apparently when processes go into the "D" state they cannot be killed because they are usually waiting for some IO to complete. I have not found any way to fix these processes while a system is running though I continue to investigate. I did find that the 2.6.25 Linux kernel will add a new TASK_KILLABLE state to help alleviate this problem. Hopefully software including KVM will be quickly updated to take advantage of this new state which functions just like TASK_UNINTERRUPTIBLE but allows the process to be killed.