Free as in freedom, not as in free beer
The essence of open source systems is that they are free. That means that the intellectual property of the virtualization product is common property and accessible to anyone. The most important advantage of open source virtualization is that anyone can access the source code and modify it. Did you ever encounter a problem in a closed-source virtualization product? Your only choice is to wait for the vendor to provide a solution to the problem. For a small company that is not too important to the vendor, that can take a long time.
In open source software, the road to solutions is often much shorter. The source code includes the email address of the person responsible for maintaining the software. You can contact this person directly and work together to find a decent solution. Chances are that solution would work much better than a one-size-fits-all patch from a vendor of a proprietary product. The only condition for such a scenario
A common misconception about open source systems is that no one in particular owns them, and hence it's not possible to get good support. Although this is true for some open source software, this is far from true for open source virtualization projects.
All of the current virtualization projects are complex and owned by one or more leaders in the software world. That means that they have companies behind them that will invest in their software and support. It is as easy to buy a support contract for a KVM implementation on Ubuntu Server as it is for VMware vSphere on Windows Server 2008. Support includes not only help in resolving problems with a virtualization system but also support for the software running in virtual machines (VMs) and the hardware on which the VMs are installed. If you've decided to virtualize an essential Oracle server on top of an open source hypervisor, this support should inspire confidence.
The most important reason to choose open source virtualization is the independence it offers. The price of vital components in a virtualization stack won't suddenly double. On the contrary, these components are likely also free. Is that the same argument as saying open source solutions are free? Partly. Proprietary solutions tend to become available for less over time. The difference is that with open source virtualization, you'll never be forced to suddenly spend your budget twice because a vendor has decided to raise its prices. Open source virtualization gives you the freedom to run the software you like at the right price. In part two of this series, I'll provide an overview of the current players in the open source market and their offerings.
About the expert
This was first published in September 2009