InfoWorld review: Virtual lab managers face off

VMware, VMLogix, Surgient, and Skytap solutions ace virtual machine configuration, deployment, and teardown, with some key differences in features and ease

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.

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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.

Real labs virtually While I've strived to highlight the differences between the products, the real feel as you sit at the console is that the products are much alike. They all accomplish the same tasks -- construction, deployment, and teardown of VMs in groups -- very well. As you'll see in the accompanying figures, they look a lot alike too. Given that their principal functions are identical, this is not surprising.

The products shared other aspects. The native versions (i.e., all the products except Skytap) were remarkably difficult to install, and in all cases the documentation was poor. The vendors clearly expect to send out technicians on any sale, but it behooves the IT organization to have managers and admins well versed in virtualization if they expect to keep operations going without spending a lot of time on the vendor support line. In this regard, Skytap is an IT site's dream. It is totally turnkey. You install nothing, and within an hour or two of taking the demo, users can be actively provisioning and productive.

All four packages were easy to use once the basic concepts were understood. Thus, the real determinants in the selection process are the secondary features. The most IT-friendly packages are Surgient and VMLogix. They have the greatest interoperability, both have license trackers, and Surgient has an extensive scheduling mechanism.

VMware's product stood out comparatively in two areas: scalability and performance. While tested on different platforms, VMware was definitely faster -- a tribute to skillful use of its linked clone design. It also has the reputation for running huge labs and being installed at many sites. However, it requires a complete commitment to VMware, as it does not manage other virtual machines. It is in many ways the barest but fastest offering in this group. It is also backed by the largest vendor in this review, if this factors enter into your selection equation.

For sites that have never used lab management software, I highly recommend trying Skytap. This will provide a hands-on experience with a small investment and no disruption to their existing infrastructure. Then, once addicted to lab management's capabilities, they might consider one of the other solutions if they don't want to be on the cloud or care to deal with Skytap's twice-monthly windows of downtime. Skytap is also my first choice for organizations that need only occasional lab management facilities, such as testing surges caused by imminent product releases.

Overall, any solution you pick will work well, and the vendors offer evaluation plans that make it inexpensive to compare and contrast the solutions in pilot projects.

Read the individual reviews for the details:

Read the first review: Surgient Virtual Automation Platform 7

InfoWorld review: Surgient Virtual Automation Platform 7 Surgient is in many ways the prototype of lab management, being the first vendor in this market, via its acquisition of ProTier in 2003. Surgient Virtual Automation Platform 7 is the latest release of the product that garnered the top rating in our reviews in 2006. The platform provides lab management for VMware ESX and Microsoft Hyper-V hypervisors. In fact, it can manage virtual machines on both platforms from the same pane of glass. The company expects within the next 12 months to add support for Red Hat KVM (Kernel-based Virtual Machine), the new hypervisor bundled with Red Hat Enterprise Linux, which marks that OEM's departure from its longtime association with Xen. Surgient has no timetable for Xen support.

From the Surgient console, administrators first outfit servers with a hypervisor. These servers are then added to the inventory of usable systems. According to its capacity, a new server is given an estimate of its capabilities, including what Surgient calls EPU, or effective processing units, which are the smallest divisible unit of computing power. The EPUs, the RAM, and the storage are then assigned to resource pools, which are management entities for hosting virtual machines. As with the other products, configurations of virtual machines can be hand-tooled by the administrator or copied from a library of templates. The virtual router discussed earlier is an optional feature for the configurations. Cloning a running configuration is a simple menu click. The Surgient console below shows a configuration and its clone running simultaneously. (Click image for closer view.)

Configurations can be set up to use a physical network address and attached as a WAN segment, so that users can access them transparently, as a wide area network, without awareness that they are using a virtual machine. Surgient uses this capability in house for its own administrative needs.

As I used Surgient, I became intensely aware of how well it has integrated itself into the fabric of enterprise IT. Not only does it support both leading hypervisors, but accessing the consoles of running VMs can be done through a wide choice of options: RDP (Remote Desktop Protocol), VNC, VMware's vSphere console access, or Citrix ICA. Deployment of VMs can be automated within Surgient or via HP Server Automation (HP's provisioning tool for enterprises) or Altiris from Symantec. Like the other packages reviewed here, Surgient integrates with Microsoft Active Directory and LDAP. It also can relay usage and performance data to most BI tools.

While the other packages have some of these IT features, none has the rich scheduling environment that comes with Surgient. The scheduler enables users to schedule a given number of machines at a specific time and be confident the VMs will be available. This option is critical in several use cases, such as education (when a class might need 30 preconfigured VMs at a set time) or doing demos from remote locations.

The only detail that gave me pause was how Surgient handles cloning. This requires some explanation. When a clone is made on VMware vCenter Lab Manager, the system saves only the delta (that is, the changes) from the base template virtual machine. This is called a "linked" clone. The reason for this design is that deltas tend to be small files, and they're easy to store economically and set up quickly.

Performance is the key, but it has a price: complexity. The complexity comes from situations in which the clone is later cloned. In the VMware product, cloning clones creates two or more generations of descendants from the original virtual machine. This works fine. When you boot the VM, the series of deltas are combined transparently with the original virtual machine, and you're good to go -- but what happens if a linked clone is deleted?

On VMware's implementation, you cannot delete the original virtual machine if it has linked clones. (The virtual machine will show up as deleted on the console and be unusable, but in the background it will continue to exist as long as it has dependent clones.) However, you can delete one of the intermediate generations of delta files, thereby marooning all subsequent generations of clones on the system. They can no longer boot.

Surgient gets around this problem by allowing only one generation of linked clones. If you clone a virtual machine, it creates a delta file. If you clone the clone, it consolidates the delta file into the virtual machine, then clones the entire VM. This neatly solves the problem, but it incurs a distinct performance penalty: Second-generation clones take a long time to create.

How much this delay is a benefit or limitation depends on how often you need to clone machines. The most common use case for frequent cloning is development and test environments. In the example of the tester cloning a virtual machine for a developer to witness a bug, the developer might then run the clone and in the debugging process take a clone of that virtual machine.

At this point, the developer crosses the threshold where VMware and Surgient take divergent paths. As a user, I prefer the VMware solution because creating a clone at these points is something you want to do quickly. As a manager, I recognize the complications of multiple generations can be costly and represent an occasional burden to IT administrators.

If you tend toward the IT perspective, Surgient has an excellent solution; otherwise, you might prefer the approach taken by VMware or VMLogix.

That concern aside, I find Surgient to be an excellent product. From an IT perspective, it is the most complete package reviewed here -- running on the major platforms and offering a broad range of IT hooks.

Read the next review: VMLogix LabManager 3.8.1

InfoWorld review: VMLogix LabManager 3.8.1 VMLogix has been providing management tools for virtualization since roughly 2004. It recently moved into the lab management market with two versions of its LabManager: One runs on native systems, while the other supports pure cloud architecture.

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