Microsoft, SiCortex, and Others: How Virtualization Helps Software Developers CASE STUDY (CLOS) Virtualization's big push to fame was arguably tools are developed, says Priedman, testing kickstarted by VMware's Workstation product early versions may destabilize a developer's which allowed individual users to run a bunch entire computing environment. of operating systems (OS), versions, or "That's the nature of the beast," he says. instances (like multiple application windows) "Almost anything except the simplest desktop Instead of having a one-at-a-time multi-boot application can crash the system. I often tell environment. In many companies, my developers that if they aren't crashing the virtualization arrived with developers first system regularly, they are not trying hard using the technology quietly to do testing and enough. We appreciate virtualization development, then introducing the virtualization tools to IT higher-ups. technologies, because they save time, and let our developers spend more of their time on Although today computer virtualization fuels the challenging stuff, not the mundane and many production environments (e.g. servers, extremely time-consuming aspects of desktop infrastructures, and as a provisioning prepping test environments." tool), virtualization is also used by a still Like other virtualization tools, Microsoft growing number of software developers. For Hyper-V lets users "snapshot the system at a starters, they use virtualization tools to "last-known good version." "We create a provide a range of target environments for rollback that allows us to restore the system development and testing (such as different to that previous good state within minutes." operating systems, OS versions, and Friedman says. "The alternative is having to browsers), and to provision/re-provision re-image the computer or re-build the configuration instances quickly and easily. environment which can take hours," says Mark Friedman, a senior software architect Friedman. "This is a tremendous timesaver." works in Microsoft's Developer Division, Friedman's group also makes extensive use of where upwards of 3,000 people create Visual virtualization and virtual machine images in Studio and the .NET Framework. Friedman quality assurance (QA) testing. "Once you get himself works mainly on the performance past unit testing by the developers, we like to tools that ship with Microsoft's Visual Studio talk about the test matrix-what versions of Team System. "About two-thirds of the people the Os does it run on, for example," he says in my division are in development and "Then we need to test against both the 32-bit testing- and most of these developers and or 64-bit versions of each. Using Virtual testers are using system virtualization (via Machine (VM) images is the fastest, cheapest Microsoft's Hyper-V technology) as one of most flexible way to maintain a variety of their key productivity tools," says Friedman, testing environments. In our QA labs, we are who is also a board director of The Computer doing this all the time, we do a lot of Measurement Group automated testing so we stockpile these One key advantage is virtualization's ability to Images as VMs, and point our test suite at set apart an unstable environment which is them. It's invaluable. We save so much time something any developer expects in early you wouldn't believe it." phases of application design. As the Microsoft Page The ability to snapshot, and restore a working image within minutes, rather than wait hours for a rebuilt system, is particularly important "You're often looking at bugs where you have to spend a day or two to set up the environment just to reproduce a bug so the time you spend having to rebuild again and again--that's a time waster," says Friedman. "That is loss of productivity." For example, when a bug causes a system crash, the developer must work backward to identify the point where the system crashed. "People often initially set breakpoints too far into the process and the system crashes again, Since a developer can easily be crashing the system several times a day, being able to restore quiddy and then re-run the debugging session while the problem is still fresh in their minds is a great benefit." Friedman says. "When you're troubleshooting a complicated bug, it's good to stay in that groove." Virtualization is a great boon to iterative testing, developers say. "We have lots of test systems for use by our developers-each of which needs its own x86 control system. Rather than get a lot of PCs, even whatever's cheapest, we're using virtualization to create VMs which then 'attach' to the external cluster boards," says Adam Moskowitz, senior software engineer at SiCortex, which builds and sells a range of energy-efficient computers. A primary benefit of virtualizing the control systems, says Moskowitz, is ease of testing "Want an experimental system? Clone a standard VM and away you go," he says. The tool set is also valuable because of its ease of configuration; developers can build a VM with the latest software once, then done it as many times as needed. Mike Brescia, who works for a company making real time environmental data recording and retrieval, says, "In addition to offering its system as a virtual appliance, our company's developers use virtualization to put up different test environments, e.g., Windows and Linux, on fewer hardware boxes. Cloning a clean computer system for testing purposes is much easier than copying a disk image and using Clonezilla, Brescia says. "Running VM does not require tearing down and wipinga complete system, we only need to be careful not to overload resources on the host machine," adds Brescia The 15 Web developers at design and marketing firm El Kirk must cater to several Web browsers and operating systems, says Connor Boyack, Ell Kirk's senior Web developer, who uses Parallels version 4 on Mac OS X Leopard, and runs VMs of Windows XP, OpenSUSE 11 and Windows 7 Beta. "Creating functional and aesthetically identical sites requires a great deal of browser testing, which makes virtualization a must," says Boyack. "Virtualization allows me to use multiple operating systems and multiple browsers all collaboratively and seamlessly." There's a huge advantage in the ability to test a dozen different scenarios simultaneously to ensure a consistent user experience, agrees Nick Gauthier, a developer at Smart Logic Solutions. "Another advantage is being able to boot up a specific version and browser when a client has a complaint. We no longer have to say 'Well , I don't run that browser, I'm on Linux', now we can say, 'One moment please; ah, I see the problem and I'm fixing it now." "Weuse virtualization to test our software on the platforms and applications we support (for QA), and to replicate customer environments when there are customer issues for support," says Eric Floehr, chief technology officer at 3X Systems, a start-up that developed and sells a remote backup appliance. "Virtualization allows us to quickly bring up and tear down environments and allows us to do so with a minimum amount of physical hardware." The ability to test against many platforms and environments with a minimum of capital outlay is especially important in a small start- up company. Plus, "It greatly improves the quality and reliability of our product," adds Floehr. There are developers acknowledge, parts of the process where virtualization can't help "One area where virtualization doesn't help is in stress testing our product, which is network-based backup appliance," notes 3X's Floehr. While we could test 10 simultaneous clients virtually, it isn't a true stress test because the 10 clients are only going through, say, four physical CPUs and two NICs, which are constraints that would not exist if they were 10 physical clients in the real world." "For load testing or scaling you have to run on the raw hardware, the physical machine," says Microsoft's Mark Friedman. "Performance characteristics, unless you expect to deploy on a VM are very different. And the same applies to the state of the art for performance measurements, you can't trust the [Physical Machines) you get on a VM currently Although. Friedman notes over time he expects this to be fixed. Also, says Friedman, the para-virtualization approach used by the virtualization industry can and does change some underlying aspects of the Os, notably the OS drivers. "So, if you have a dependency on specific drivers or hardware environment that will be impacted. For example, there's a virtual NIC, and there's a specific driver. The driver is 'virtualization- aware. You must understand that if you need testing against a native set of drivers, you won't see that within a VM. So, this impacts people doing driver development, but not web developers, etc." Despite those quibbles, virtualization already gives developers real benefits "Virtualization makes our developers more productive once they learn to work with the technology," says Microsoft's Friedman. "It allows them to spend more of their time in coding, testing, and debugging. It eliminates a lot of time and delay spent in set-up and preparation, which isn't where we want them to be spending the bulk of their time." SOURCE: Daniel De How Virtual proves Sohn Development.com wwy 11 2009 Questions 1. How does virtualization work? In your own words, describe what you understand about the virtualization process as depicted in the case. 2. In software development and testing where does virtualization help, and where it does not? Why? 3. What are the business benefits of implementing virtualization technologies in software development? Classify them into those that enhance the effectiveness and the efficiency of the development and testing process