Several different virtualization technologies support server consolidation. One of the most popular is Guest OS Virtualization, a technology that lets you run multiple operating systems on the same host server or hardware system.
While this technology provides overwhelming support for server consolidation, it can also add to the server proliferation problem because now, you'll have host servers to manage in addition to the virtualized machines that provide services to your users.
Another option to consider for reducing server sprawl is application virtualization. Application virtualization creates software or service isolation on top of the operating system, which also provides support for application consolidation.
Typically, application servers are proliferated because each time an IT department decides to create, build or update an application -- especially mission-critical applications -- project managers insists on bringing in their own servers. Often, they bring in multiple instances of servers: servers for operations, servers for development, servers for testing and so on.
The main reason for this is distrust; each project or department does not trust their application to co-exist with those of other departments on the same server. In addition, each project does not want to share development space with others in the organization.
Using application virtualization, you can begin to reduce the number of servers required to run in-house applications, especially legacy in-house applications that are often built with older coding practices. You do this by virtualizing each application and hosting it on the same server. You can also rely on Guest OS Virtualization to move all test, development and even production servers to virtual instances of the OS, further reducing the number of servers you require.
An application virtualization sandbox
Remember that guest OS virtualization creates a layer that protects the actual hardware from the virtualized OS. In the same way, application virtualization acts within the operating system to create a protection layer from any changes made by the application software itself.
The most significant feature of application virtualization is that it sandboxes software and isolates the OS from the changes the software would normally make when it is installed. Put another way, application virtualization tools isolate or abstract application components from the operating system and other applications, yet provide full capabilities for application and operating system interaction.
An application virtualization sandbox
Application virtualization does not actually install software on a system or capture the installation process for software. Instead, it captures the installed state of the software. That's right. Application virtualization captures everything that is needed to make the software run on a system, but without making system changes.
This capability represents a tremendous advantage during operating system migrations or consolidation projects. It vastly reduces your system and application preparation time while ensuring that applications that are known to cause conflicts with each other will operate together on the same system. That's the good news. The bad news is that to take full advantage of application virtualization, you will still need to redeploy all of the applications you run. This is why it is an ideal technology for migrations or consolidation projects.
With application virtualization, you still invest hours and days of effort preparing and installing and post-installation testing. But this time, you only need to do the work once. In addition, once deployed, the application will not change anything on the OS. Not that has to be worth quite a bit of effort, right?
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|Danielle Ruest and Nelson Ruest are IT professionals specializing in systems administration, migration planning, software management and architecture design. They have written several books and are currently working on the Definitive Guide to Vista Migration for Realtime Publishers as well as the Complete Reference to Windows Server Codenamed "Longhorn" for McGraw-Hill Osborne. They have extensive experience in systems management and operating system migration projects. For more tips, write to them at firstname.lastname@example.org.|