VMware is a software package that allows you to run multiple virtual machines on a single physical machine. This means that a single computer could simultaneously run multiple instances of Windows and Linux. The software treats each virtual machine as a completely independent computer, with its own dedicated memory space and virtual hard drive. You can even format a virtual hard drive without interfering with the physical machine or with any of the other virtual machines. Now VMware takes this concept to the server space with the introduction of VManage.
Typical virtual machine uses
I've used virtual machines extensively in my writing career (although not always VMware). As a technical author, I'm often asked to test a variety of products. Rather than risk having a poorly written application crash one of my production systems, I run such applications on a virtual machine. I keep a file handy that has a virtual machine configured to my specifications. When I test an application, I install and run it on this virtual machine. When I'm done, I just blow it away.
Another way that I put virtual machines to use is with running multiple operating systems. For example, last summer one of my editors asked me to write a series of articles on Linux. Since I'm a Windows guy, I didn't have any machines that were already running Linux. I didn't want to go out and buy another computer because my computer room is already hot and crowded enough. Reformatting one of my existing machines wasn't an option either. Ultimately, I decided to run Linux within a virtual machine on a machine that was natively running Windows XP.
VManage is server virtualization
Perhaps one of the most common uses for virtual machines is server consolidation. For example, imagine that you have five servers running Windows NT 4.0. Now further imagine that the hardware on these servers is aging and is starting to become unreliable, but replacement parts are no longer available because the servers are so old. You could go out and buy five new servers to replace the five aging servers, but what's the point? The server software is running fine on the old hardware, and much of the power of a new server would be wasted if you were just going to be running Windows NT 4.0. You could try migrating all of the server software to Windows Server 2003, but that tends to get a little expensive, and there is some older software that simply won't run on a newer operating system.
You could, however, solve the problem through server virtualization with VMware's VManage solution. You could buy one server and one license of Windows Server 2003, and then you could use VMware to create five Windows NT virtual machines. You would then be able to condense all five of your aging servers into a single box, but would still be able to maintain each server's individuality because each is running within its own virtual machine. To accomplish this task, the VManage solution contains two remarkable features.
I admit that for a long time, I thought of virtual machines as a poor man's tool used by IT pros who either couldn't afford or didn't have space for additional hardware. However, VMware offers several other products that make it obvious that server virtualization is a concept worthy of even large enterprise environments.
One such product is VirtualCenter. VirtualCenter is basically a management component for virtual servers allowing administrators to centrally manage all of the virtual machines in the organization.
The nice thing about VirtualCenter is that it allows you to view resources each virtual server is consuming. It also allows you to set triggers and alerts for situations in which a virtual server might be consuming too many resources or might become unavailable. VirtualCenter even offers a reporting tool that you can use to spot resource contention issues.
One of the best features of VirtualCenter is that it allows you to deploy new virtual machines based on prebuilt templates. The reason this is so good is because it's both a time-saver and a great way of implementing security. Imagine that you have to deploy 15 Windows 2003 Servers onto 15 separate virtual machines. As we all know, installing Windows is only the first step in a very long process. You must also typically install service packs, hot fixes, antivirus protection, and any other standard application that your organization might rely on. VirtualCenter allows you to create a single virtual server and then use that virtual server as a template for the other 14 machines. The nice part of this feature is that you won't have to worry about accidentally forgetting to install some critically important component onto one of your other virtual machines because it will already be included in the template.
Another tool that makes it obvious that VMware is an appropriate solution for enterprise environments is VMotion. VMotion is a mechanism that allows you to seamlessly move a virtual machine from one physical server to another, assuming that both physical servers are connected to a common SAN. There are several key benefits to this technology.
First, it greatly simplifies hardware maintenance. If you need to take a server down for a hardware upgrade, you can simply associate the virtual machines running on that server with a different physical server. This would then free up the server that had been running those virtual servers so that you can work on it without disrupting the user's work. As if this feature weren't nice enough, the way that VMotion is designed provides zero downtime during the transition between physical servers.
Another key benefit to VMotion is load balancing. When VMotion is used in conjunction with VirtualCenter, all servers can be monitored for resource utilization. If one physical server is being bogged down by performance demands, some of the virtual machines residing on that server can be automatically moved to a different physical server that has sufficient resources available. Again the transition occurs with no interruption of service.
Pricing and availability
VMware's line of virtual server products is not available directly through the VMware Web site. For price and licensing information, you must contact VMware at 1-877-4VMWARE, or you can e-mail VMware at Sales@vmware.com.