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
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
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.