Thursday, June 18, 2009

The new kid on the virtualization block

Last week, I happily upgraded my Linux installation to Fedora 11. As usual, this wasn't driven by any requirements, just by the fun to have the latest and greatest. (Do I hear Anjas "MEN!" :-) On the whole, things have improved. For example, my UMTS stick is now working out of the box. Monitor switching at work is now working nicely.

An obvious minus, however, is the integration of VMware. I am using VMware server 1, which is almost unsupported on Fedora in general. In particular, it it unsupported for Fedora 11. As usual, it was no problem to find a matching kernel patch. But, what a surprise, it is no longer sufficient to patch the VMware modules: You need to patch the kernel as well. Ok, I detected the procedure within one hour. But that means, that I will have to compile my own kernel with any kernel upgrade. Given the frequency of kernel updates on Fedora, I'll likely recompile every two weeks or so.

Brings up the question for alternatives. I have tried VMware server 2 in the past, but was definitely disappointed, because it is both a resource hog (for example, more than 400MB on disk!) and the lack of the former vmware-console just adds on. Nevertheless, I tried again. Just to detect that the same problem seems to be present: The kernel modules fail to load with the same error message of a missing symbol.

I never tried VirtualBox before, but this seemed to be a good enough reason to do it now. First impressions have been quite positive, until I tried to start a VM with a windows guest system. Obviously, that's not so easy: To get it work, you have to change some settings, fiddle with the windows registry (of course, before starting Windows ...) and similar niceties. Again, that's not what I'd like to have as a standard procedure. VM's should be easily adoptable from or given to colleagues.

So far, I was sticking to VMware server 1. But today, I detected the announcement of VirtualBox 3 beta. And, hard to believe, it just works, even with Windows guests imported from VMware. I think, VMware lost a user...

Monday, June 8, 2009

Automatically compiling VMWare modules

VMWare does, in general, an excellent job. It runs smoothless on my machine, generally being one of my best work horses. In particular, with VMWare Server coming at no cost.

There's an exception, though: The kernel modules. As usual, the problem doesn't exist on a Windows host (or guest, for that matter), but you've got to know how to deal with it on a Linux host. VMWare depends on a number of kernel modules, for example vmnet.o, which creates the virtual network interfaces. In theory, these modules are delivered as part of the VMWare distribution for a variety of Linux distributions. In practice, I am unaware of any example, where these precompiled modules could been used: I always needed to compile them for myself.

Ok, that's not too much trouble (at least not, if you've been able to obtain the right patch for your system, typically after a lot of Googling), basically all you need to do is to run (on the host) or However, one problem is still left: The procedure of recompiling the modules needs to happen after any Kernel upgrade again.

But here's a solution: An init-script, which is invoked before VMWare starts upon every reboot. The script checks, whether there are modules matching the running kernel. If not, is invoked with the necessary options for batch mode.

To install it, download the script here. Store it as /etc/init.d/vmware-kernel-modules. On Fedora-Linux, create the necessary links by running /sbin/chkconfig --add vmware-kernel-modules. On other distributions, this must be done manually.