How to Tame Virtualization Sprawl

The benefits of virtualization are eroded when virtual machines go unchecked. 

Companies have embraced virtualization for the many efficiencies the technology brings to the data center. But with the increasing use of virtualization comes an increasing challenge: managing and securing all those virtual server instances.

In fact, the benefits of virtualization are eroded when virtual machines are not controlled by a life-cycle process.

VM sprawl-the creation of VMs without regard for ongoing utilization monitoring, desired-state configuration management, or an automated process for correlating VM and physical host performance characteristics-can be remediated in a cost-effective manner if IT managers get the balance right between ease of VM creation and management oversight.

What follows are best-practice suggestions based on eWeek Labs' virtual testing implementation and tips from virtual infrastructure users and management vendors.

To read Cameron Sturdevant's tips for how to set up server virtualization from the beginning to avoid later problems, click here.

The bottom line for IT managers is that VM sprawl can be controlled, but only if IT expertise is combined with an almost ruthless adherence to procedures designed to enforce standard configurations, maximum resource utilization and dynamic reallocation of computing capacity.

The Physical and Virtual Relationship

Consolidating workloads that currently run on underused physical systems is what makes virtual systems so attractive. In a Ziff Davis Enterprise Editorial Research survey conducted for eWEEK, 75 percent of respondents said that improving server utilization was among the main drivers leading to a virtualization implementation at their organizations.

Long after the honeymoon with virtualization ends-that is, when maximum physical server utilization is achieved-it may be that management efficiency will rise in importance for virtualization projects. IT managers will have to use management systems to ensure that virtual systems are maintained in a desired configuration state that includes security and operational patches to both the operating system and applications.

In other words, virtualization drivers that scored low on the survey-including lowered staff costs-will become much more important when server utilization and the accompanying hardware cost reductions are driven out of the equation by widespread use of virtualization.

The virtualization market is heating up. Read more here.

The management question is critical because there is a relationship between physical resources and VMs. This is especially true of VM performance. Unused CPU cycles, excess network bandwidth and underused RAM create the virtual real estate upon which entire "cities" of virtual systems have been created. Virtual server sprawl is created when management systems designed for purely physical systems don't keep up with tracking the relationship between physical machines and VMs.

Transforming traditional physical management into a hybrid that manages both physical machines and VMs is the first step in controlling sprawl. But it's not the only step. Sprawl is created if there is a loss of control after the machines are created, if there is no orderly plan for maintaining machines in a desired configuration once they are placed in production, or if machines are abandoned but not decommissioned when they are no longer used.

The question of when to terminate a VM is most applicable to test and development environments, where there is a need to ensure the orderly decommissioning of virtual systems. As projects end, IT managers will need to take down unused systems so that physical compute resources can be reallocated. IT managers should ask project leaders to specify a date when the virtual system will be turned off and to use management tools to monitor server utilization. Ferret out owners of unused systems to ensure they have a legitimate need for the resource.

However, before virtual systems are taken down, they must be created, which is also one of the best places to start managing virtualization.