AUTOMATION SOFTWARE – VMWare: Computer virtualization
June 14, 2007
By Jeremy Pollard
While hardware resources are getting less expensive, software licensing, maintenance and administration are not. In any given application, there may be multiple computers required. And there may be many situations where you wish you had a test computer to run or test applications without disturbing your main machine, while retaining access to all of the hardware resources you have.
Remember DesqVIEW, a Quarterdeck development product? It was a DOS-based program that allowed users to run multiple programs on the same computer. DesqVIEW “virtualized” each DOS session in its own logical memory space. It was just like having more than one computer.
To have multiple sessions now, you need Windows for the software portion and VMWare for the hardware virtualization part of the equation.
The VMWare server is a free product that runs on top of an existing operating system, such as Windows 2000 or Windows XP Professional. Once installed, the software allows you to create a virtual machine (VM) that you can access from a remote machine or local computer.
Imagine having a physical machine that you can split into many different environments. One VM could run Windows 2000, and another Windows XP. Linux, Sun Solaris, Novell and other operating systems are supported. The host operating system is needed to support the VMWare server only.
Once you download the server from www.vmware.com, and install the software with the defaults, the fun is ready to begin.
You can connect to a local or remote VMWare host for administrative purposes. Configuring a VM is fairly simple, but there are a few things to consider. Depending on what applications you want to run, the amount of memory you need to allocate may outstrip the available memory. Memory is not dynamically allocated, so you have to be careful how much you give to the VM.
The allocation of such resources as hard drive space, network connectivity, CD ROM drives and power control need to be configured. Once that is done, the only thing left to do is install the operating system of choice. To do that, insert the operating system media into the device of choice and start the VM. It will boot and install the operating system, and then you configure and install the software you need for the VM. Once the software is installed, you can run it concurrently with the host software applications and any other VMs that may be running. And you can change the configuration environment at any time.
I would suggest adding a virtual disk to store the common data files that the VMs are going to use.
Once you have created the VM, you can access the VM locally from the keyboard and screen of the local host, or use remote desktop protocol (RDP) to remotely access the VM.
This is where it can get really interesting. Many thin clients are available for under $200, allowing you to access the VM remotely. Thin clients have no hard drive and use software from a remote device.
Virtualizing hardware can be used in various ways. You may want to test a new piece of software without affecting your current machine state. Or you may want to test certain software under different operating systems. You may want to create a local server with multiple VMs and have each remote client connect to their own VM. Or you could use RDP to have multiple clients connect to the same VM.
Duplicating the VM is as simple as copying and renaming the directory that is created. VMWare provides a management console to help with these tasks, but it is not free. In addition, software licensing is your legal responsibility since virtualization is licensing neutral.
I was up and running in less than 10 minutes with two XP Professional VMs. For more than a few VMs, VMWare’s ESX server virtualization operating system will manage the host hardware more efficiently.
I enjoyed using this product so much that I’m keeping it installed.
Name: VMWare Server
Jeremy Pollard is a 25-year veteran of the industrial automation industry. He has worked as a systems integrator, consultant and an educator in the field. Jeremy can be reached at firstname.lastname@example.org.