Impact of Virtualization in IT

Current Landscape

Low-level virtualization technology is maturing has been around for nearly 10-years for Intel-based hardware. Several virtualization products are emerging as leaders. As the virtualization options and technologies have matured, the word has spread and mainstream businesses are making the move to virtualization.

While low-level virtualization technology appears to have reached a degree of maturity, the business challenge of deployment, management, and maintenance of virtualized systems is not so well understood by many. Businesses see potential benefits to virtualization, but there are obstacles to successfully implementing virtualization solutions.

Benefits

Virtualization is pursued by business because of the many potential benefits.

Server Consolidation

The workload from underutilized machines can be combined into a single physical system. Fewer physical servers are needed, and various cost benefits arise as:

• Power consumption is reduced
• Less physical space is needed
• Hardware expenses are reduced

Disaster Recovery/Continuity

Virtualized servers require less downtime due to maintenance or hardware failure.

• Standby virtualized server instances can be activated readily.
• Virtual servers can be migrated to other physical hardware.
• Full backup images can be created and easily restored onto other physical servers.

The overall result is higher availability, and reduced downtime.

Testing/Simulation

New configurations can be created and tested inexpensively in virtualized environments. Test configurations can be identical to production configurations without necessarily requiring identical hardware.

Custom test configurations can be created and deployed on demand without the need to maintain many physical test servers with individual configurations.

Flexibility/Scalability

Additional server instances can quickly and consistently be deployed as business needs change. Server images can be pre-configured and added to the total capacity of a server environment when designed with scalability in mind.

Legacy Support

Legacy software can be preserved without needing to maintain aging hardware. Underutilized legacy servers can be consolidated an efficiently utilized on virtualized servers.

Isolation

Specific software packages can be isolated in individual server instances. This allows applications to be maintained and upgraded individually without risk of conflicting with other services.

Isolated server instances can also be secured and protected such that failure or intrusion in one instance does not affect others.

Applications can be packaged as "appliances" which are simple to deploy—not requiring installation and heavy configuration.

Challenges

Virtualization offers many benefits, but poses many challenges as well. Businesses may not be well prepared or equipped for handling the challenges related to virtualization. A key to understanding the challenges is realizing the server virtualization provides flexibility that can lead server environments to become much more dynamic—meaning all of the supporting infrastructure needs to be equally dynamic.

Training/Technical Support

As with all new technology, employees need to be trained to understand how to effectively deploy and maintain a virtualized environment. New methods and creative thinking may be necessary. Likewise, external vendors may not be prepared to support software and hardware configured with virtual servers.

Management

Management of virtual servers can become challenging quickly. In addition to application configuration that is necessary for individual servers, managing the virtualized environment encompasses many details.

• OS images
• Backups of virtual servers
• IP addresses assignment
• Allocating physical machine resources
• Migrating virtual servers between physical machines

As the number of virtual servers increases, performing such tasks can become unwieldy.

Network Administration

Network administration may need special consideration when maintaining numerous virtual servers.

• LAN design
• IP addresses assignment
• Name resolution of virtual servers
• Bandwidth usage on LAN segments

Such considerations may need special care a virtualized environment due to the inherent flexibility of creating and modifying virtual servers. Where adding a physical server to a network would normally result in fixed network requirements (e.g. hostname, IP address), virtual servers can be quickly created and destroyed and network configuration needs to be just as flexible. A single physical machine hosting virtual servers is likely to use multiple IP addresses, host names, and provide multiple services.

Monitoring

As one of virtualizations main benefits is to maximize server resources, monitoring of server utilization is key. It is necessary to see that physical servers are not overloaded, and that virtual servers have the resources they need. As virtual server usage changes, resources need to be balanced and machines should be migrated as necessary to maximize resources.
Related is the need to monitor individual services running on virtual servers. Considering that the virtual server environment may be more dynamic than traditional environments, additional care is needed to maintain proper monitoring.

Complexity

In many ways, virtualization adds complexity to the environment—tracking network configuration, multiple layers of software (hypervisor, virtualized OS), numerous virtual servers to configure, monitor, patch. More complexity can mean more time spent managing the environment.

Compatibility/Licensing

Although virtualization technologies are reasonably stable, there are always potential problems stemming from hardware and software compatibility issues.

Tracking software licenses can be more difficult as well. It is very easy and fast to deploy new virtual machines—deploying a second copy of Microsoft Windows is as easy as starting up a second instance of a virtual machine.

What Needs To Be Done

With the advantages in mind, businesses are starting to face the challenges of virtualization. There may be significant costs to businesses that implement virtualization. There is a learning curve, and there is a need for tools and services to help businesses through the challenges.

Tools that address the issues exist at different levels. Technology vendors are moving toward virtualization and businesses appear ready to follow.

References

http://btquarterly.com/?mc=virtualization-big-picture&page=virt-viewresearch
http://www.btquarterly.com/?mc=pros-cons-virtualization&page=virt-viewresearch
http://www.cbronline.com/article_feature.asp?guid=609D18C1-C9F9–42A5–9BE3-B5B3B781C91B
http://www.builderau.com.au/strategy/architecture/soa/Grid-computing-A-skeptic-s-perspective/0,339028264,320280601,00.htm
http://www.networkworld.com/news/2007/102607-arguments-vmware-xen.html?nwwpkg=50arguments

—Posted by Adam Lane on Nov 6, 2008

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