InfoWorld review: Virtualization for development and test

As virtualization continues its fast run at transforming IT, many organizations are starting to employ the technology to create and manage transiently configured systems. These systems are typically assembled for a one-off project and torn down at project end. Virtualization is an almost perfect match for this need. IT organizations that employ virtualization for temporary systems rely on software packages called virtual lab managers, or just lab managers for short.

The term "lab managers" doesn't quite describe all of the purposes these solutions are good for. The use cases for temporary virtualized systems cover a wide spectrum, including development, testing software, reviewing new products, running demos, doing in-house instruction, and so on. Lab managers simplify buildup and teardown, while providing many other services whose needs are not easily anticipated until you deploy virtual machines this way on a regular basis.

For this review, I looked at VMware's Lab Manager (which I reviewed in 2006, when it was still sold by the soon-to-be-acquired Akimbi); Surgient's Virtual Automation Platform (which I also reviewed in 2006); LabManager from VMLogix, a newcomer to lab management tools but a pioneer vendor in virtualization technologies; and Skytap, whose product is entirely cloud-based. I found that the products were excellent solutions that greatly simplified management of nonproduction virtualized systems.

How lab managers work
Lab managers are built around several basic features, all of which are implemented in the reviewed products. The software generally runs on its own dedicated server and interacts with a pool of virtualization resources (servers and storage), as well as with a dedicated storage server that holds artifacts I'll describe shortly. In sum, the minimum standard configuration consists of at least three systems: the lab manager, the storage server, and the virtualization host or hosts.

When virtual machines are created on the host, they are implementations of templates housed on the storage server. (A template might be a Red Hat server configured with three NICs and running Tomcat.) When the need arises, an admin will select a group of templates to instantiate into virtual machines. If this group of virtual machines -- for example, a database server, Web server, and a client machine -- is to be handled as a single entity, the virtual machines are bundled into a management unit called a configuration. This configuration can be saved to the storage server and, later, run as a single unit.

When lab manager products create a configuration, they optionally bundle a virtual router into it. This router provides network address translation (NAT), which is necessary in the event that two instances of the same configuration are run simultaneously. The NAT in the virtual router maintains the IP addresses of the individual virtual machines inside the configuration, while exposing them outside the configuration as translated addresses. This translation prevents the conflicts that would normally arise when two virtual machines with the same IP addresses run on the same network segment. Additional software built into the configuration similarly handles the problem of multiple instances of MAC addresses.

A key feature of lab managers is the ability to take snapshots of running configurations and thereby create clones. On-the-fly cloning is invaluable in testing and QA, where a test engineer can take a snapshot of a bug when it appears and forward a link to the cloned configuration to the developer for remediation. Like VM templates, these snapshots are saved on the storage server. (They could be kept anywhere, actually, but a storage server under the care of a lab manager can enforce access control, inventory management, lifetime duration, and so on.)

Lab managers can perform many other small tasks, such as security, auditing, and the like, but their primary function is managing VM templates, configurations, and individual virtual machines in a convenient fashion.