Home | Forums | Article Search | Subscribe & Shop | Contact Us | Log Out Open Sauce Email This Print This View My Personal Library Loading Zone May 2006 • Vol.6 Issue 5 Page(s) 81 in print issue Add To My Personal Library Open Sauce Virtual Machinery Jump to first occurrence of: [VIRTUALIZATION] Here’s a question: X is to “proprietary OS computing” as “open-standard Internet” is to “proprietary LAN.” The answer is “open-standard virtualization.” The open-standard Internet interoperably connects everything to a global network that makes proprietary LANs look sick. The concept of sharing computing resources among many users is almost as old as the mainframe: Sub-divide resources to share among individual users without having their programs interfere with each other. If one program eats memory, you don’t want it eating everyone’s memory. Open source and open standards give old ideas new life, including virtualization. Instead of sharing very limited mainframe computing resources among many users, we have many apps running on PCs bumping into each other—or else under-used, single-purpose servers requiring costly maintenance. Virtualization software sits between the app and the host hardware/OS platform letting you set up a VM (virtual machine), a software abstraction on which you can install an OS and whatever apps or services you want. Each VM gets a share of hardware in the form of a standard “configuration,” including RAM, CPU capacity, and access to system resources, such as storage and networking. Incompatible apps (and OSes) happily run on the same hardware but inside different VMs. An app may crash its VM, but it won’t affect what’s running in other VMs. Businesses see great benefits in virtualization; it improves hardware utilization, a big selling point for vendors who claim single-purpose hardware servers run at 5 to 15% of their capacity. Consolidating multiple services and servers into one system can remedy this gross underutilization of expensive resources. Virtualized servers are easy (read: “cheap”) to maintain. You can port VMs from one physical computer to another by copying a file. You can also use virtualization software to consolidate multiple computers to act as a single VM, so scaling up is much easier, and you can access excess capacity on demand. Other benefits include running an app in isolation to remove bugs that incompatibilities with other software cause. You can also make decisions about upgrades independent of apps. You can retain an app running under an OS-hardware combination in a VM independent of any upgrade of the underlying hardware or OS. Why will open-source virtualization do for computing what the Internet did for networking? Because open-standard virtualization makes apps completely independent of, and interoperable with, the rest of the world. The same goes for all your computing resources. A Linux print server, a WinXP Apache application server, etc. all run on whatever hardware you put into the virtual computing resource pool. Apps are portable, and computing resources are fungible. Using a proprietary VM architecture, such as those VMware and Microsoft Virtual Server 2005 offer, means you’re locked into using only the platforms it supports as hosts and only the OSes it allows in its VMs. VMware, with its broad Linux support, likely has the corporate will to do well if the market chooses an open standard for virtualization. Even though Microsoft announced last year planned support for some Linux versions “in the future,” it may take longer to accept an open virtualization standard. The commercial/proprietary virtualization market, with companies such as Virtual Iron and SWsoft joining the fray, almost universally acknowledges the presence of a strong open-source contender on the horizon, either by offering some of their software under various no-cost licenses or by explicitly supporting the leading open-source virtualization project: Xen. Xen takes a different approach to the problem of performance under virtualization. Xen requires OSes be slightly modified to run as VMs. Novell SUSE and Red Hat, among others, already offer Xen support. Microsoft could (in theory, at least) modify Windows to run under Xen relatively easily, but I’m not holding my breath. By being open, Xen offers the potential for complete and seamless interoperability between resources and applications. Xen’s success in penetrating corporate markets is due to XenSource, a well-funded startup that the original Xen development team founded. Can XenSource profit by promoting an open standard for virtualization? If it means you can run any application under any OS on top of any hardware from any vendor, the answer is clearly yes. You can get saucy with Pete at pete@cpumag.com. Pete Loshin, former technical editor of software reviews for Byte Magazine (print version), consults and writes about computing and the Internet. He also runs www.linuxcookbook.com. He owns shares of both Microsoft and Red Hat and believes that Windows isn't for everyone, but neither is Linux. Want more information about a topic you found of interest while reading this article? Type a word or phrase that identifies the topic and click "Search" to find relevant articles from within our editorial database. 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