by Laurianne McLaughlin

Virtual Software Appliances: Why They Could End Deployment Hell

Jan 08, 20089 mins
Enterprise ApplicationsVirtualization

Many enterprises still don't like SaaS, but now there's an up-and-coming alternative, virtualized software appliances, that deserves attention. Here's why it might not be long before you buy software pre-packaged in a virtual machine.

Will the way you buy and deploy enterprise software change again? Analysts say yes, and it’s thanks to virtualization technology.


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We’re not talking about software-as-a-service (SaaS). As much as many IT executives dread the traditional software deployment process, some never bought into the concept of SaaS, citing customization, security and cost concerns, among others.

However, enterprises may like the up-and-coming alternative—software sold as a virtual appliance. This means an application is designed, certified and delivered, with its own little OS, to run as a virtual machine on your existing physical server, or to run in a VM via a “cloud computing” service like Amazon’s.

Billy Marshall, CEO of rPath, bets that enterprise IT will fall hard for virtual software appliances. And analysts say his vision is grounded in reality, not hype.

RPath provides an open-source platform and infrastructure services to software vendors who want to provide their apps as virtual appliances. Current customers include Zimbra (maker of collaboration and messaging software) and Openbravo (ERP software).

“Virtualization is definitely going to become the bottom layer in the software stack,” says Marshall, who served as Red Hat’s vice president of North America sales from 2001 until 2005 before founding rPath. “It’s inevitable because it provides so much flexibility to the customer.”

Sure, IT leaders have heard sweeping predictions about software deployment before. But consider the current situation: Most IT leaders already understand the flexibility and maintenance advantages of virtual machines. And neither vendors nor customers like today’s traditional software delivery model.

It takes vendors too long and costs too much to test and ship new versions given the multitude of configuration environments. As customers, you’re forced into a never-ending maintenance cycle and are either nervous or forbidden to tinker with the environment if you want support from your core application vendors. Those are just the starting problems.

Meanwhile, enterprises see great cost and flexibility benefits from virtualization (see our recent survey: Your Virtualized State in 2008). However, some application vendors won’t support their applications yet on all virtualization platforms. For instance, SAP only recently announced support for its products running on VMware; Oracle says you’d better use its virtualization technology if you want support on Oracle apps.

Software vendors who want to keep customers happy will need to certify their apps for use with the various hypervisors and virtualization platforms—but that might not be easy or cost-effective. Already, VMware, Citrix/Xen and Oracle virtualization platforms exist and soon Microsoft’s technology will join them. (A hypervisor is a piece of software that serves as an abstraction layer between a physical machine’s host operating system and the rest of the software and VMs on a machine.)

Because it serves as a buffer, the hypervisor is a key ingredient in a virtualized environment. But not everyone agrees which vendor’s hypervisor is best, and customers want the freedom to choose.

That’s where Marshall’s company comes in, simplifying the work for the ISV. His vision looks like this: You—the customer—get to pick the hypervisor for the VM: VMWare, Xen, Microsoft, whatever you like. But the software vendor controls the software stack. Otherwise, it costs the software vendor too much, he says.

Pros and Cons of Virtual Software Appliances

Will CIOs accept the idea of more software being delivered via virtualized appliances? “CIOs have already accepted hardware appliances,” Marshall says. “They’ve also accepted SaaS. This is middle of the road between the two.”

That’s a peek at how the software vendors will pitch you on it. Unlike a hardware appliance, there’s no extra physical item to track, maintain and secure. Unlike SaaS, you can keep your physical server with the VM on it within arm’s length if you want.

Don’t just dismiss this idea as the new fad, says James Staten, a Forrester Research principal analyst. “CIOs should change their thinking about software deployment from deployment on traditional servers to deployment on virtual servers first,” Staten says. “This change in thinking is fundamental and will be the predominant way of deploying anything in the next five years. Whether they deploy applications in their own data center or onto hosted infrastructure such as the new cloud computing offerings from Amazon, Layered Technologies or others, the default deployment will be the virtual server.”

Software delivered via an appliance will deliver “dramatically easier installation,” Staten says. The next step? “CIOs should think about whether they should ‘appliantize’ their own applications, as that will make deployment and redeployment of their own software easier,” he says. “What comes as a byproduct of this thinking is greater OS freedom as the appliance is self-contained and can thus leverage whatever OS is best for that application, and application development can tune, optimize and strip down the OS to maximize performance and security.”

Of course, this game has just started: Virtual software appliances is an emerging market, says IDC Research Analyst Brett Waldman, representing almost none of the overall software market right now.

IDC predicts that will change to “a fraction of a percent” by 2011, worth about $687 million in revenue worldwide, he says. “But remember, getting to almost three-quarters of a billion dollars in only a few short years is a pretty remarkable achievement for an emerging market,” Waldman says. “We are bullish on it, but this will take time.”

The software market changes quite slowly, plus enterprise customers have to be very comfortable with virtualization—for example, with tasks like live migrations of VMs between machines, Waldman says. (IDC and share the same parent company, IDG.)

To consider the big picture of what this new model means for you, think about a hypervisor on a physical server as a sort of USB bus, Marshall says. You can plug a bunch of software virtual appliances into that bus. They won’t step on each other, running independently in their own VMs, though they will of course all grab memory and CPU power from the physical server.

Lots of Activity Among Virtualization Vendors

Are the hardware and hypervisor heavyweight vendors liking this picture? You bet. Already the hardware vendors and hypervisor vendors are working together to create new standards for making the various pieces of software and hardware share management information. And you should expect more cooperation in 2008, Marshall says.

A management standard in this arena would simplify work for the hypervisor and hardware vendors and, ideally, help an application pass critical information to the hypervisor—for instance, the minimum share of memory and CPU resources that it needs, Marshall says. “The hypervisor has to let the team members (applications) communicate with each other,” he asserts.

A standard called Open Virtual Machine Format (OVF) is the start of this process, Marshall says. A draft specification of the OVF standard, created by companies including Dell, HP, IBM, Microsoft, VMware and XenSource, has been accepted by the Distributed Management Task Force (DMTF) standards organization.

The DMTF describes the basics of the standard in this way (in its press release announcing the standard): It “uses existing packaging tools to combine one or more virtual machines together with a standards-based XML wrapper, giving the virtualization platform a portable package containing all required installation and configuration parameters for the virtual machines.” (Click for more details on the standard.)

The hardware vendors have financial incentive to encourage this software as a virtual appliance model as well, Marshall predicts. “Dell has historically not been able to sell much server software because the software is so complicated,” he says. “When a hypervisor becomes the bottom layer, Dell can also install virtual appliances on top. They can tell a customer, ‘If you like them, buy them.’ It’ll start with simple applications like wikis, maybe a CRM or content management app,” Marshall says. “The good thing is, these virtual appliances don’t take up resources unless you run them.”

Linux: Ideal VM Base?

As for exactly what should be at the core of the virtualized software appliance, expect a lot of debate about whether a general-purpose OS or a “just-enough” OS is right, Marshall says. He argues that his just-enough approach, or jeOS (pronounced juice), makes sense for footprint and security reasons, for starters. “A general-purpose OS has to have everything there, just in case,” he says. “It creates security and maintenance work.”

RPath’s JeOS approach uses a small slice of Linux as the base operating system for the software virtual appliance. Not a full version of Linux, but just the code needed to deliver and handle the software on the appliance. In a blog post that describes his argument for jeOS, Marshall argues that you should think of it not as an operating system but as a “packaging architecture”—free of the “dependency hell” that maintenance of general-purpose operating systems forces upon enterprise IT groups. Or, as he puts it plainly in another blog post: “Maintenance doesn’t have to suck.”

With a software appliance that uses the jeOS approach, the customer loses a little bit of flexibility, he says, but gains the advantage of avoiding hundreds of security and maintenance patches and updates to the general-purpose OS.

Guess who this vision impacts in the end? Yes, Microsoft, whose general-purpose OS you are probably running on your servers today, unless you have already moved to Linux.

But rPath’s biggest direct competitor is the status quo, Marshall says. In other words, it will not succeed if the software vendors decide to skip the software appliance route and instead certify all those various hypervisors and deliver software in the traditional way. Of course, Marshall believes that choice makes little sense.

Successful SaaS vendors have already learned the lesson regarding lowering the cost of certifying and supporting the product on a slew of platforms, Marshall says. “Marc Benioff (CEO of is laughing all the way to the bank,” Marshall says. “He certifies against one thing: his infrastructure.” That means he spends between 8 percent and 9 percent of revenue on R&D, whereas most software vendors spend between 15 percent and 18 percent, Marshall says.

But rPath faces other rivals as well, Forrester’s Staten notes: “There will soon be appliance toolkits from VMware, Red Hat and others,” he says. “This will breed differentiation which will make it anyone’s market to win. They (rPath) will have to be open, flexible, quick to market with new capabilities and incredibly responsive to their customer’s needs.” Toolkits, along these lines for enterprise customers, not just ISVs, will also arrive, though more slowly, and that market could be vastly bigger, Staten believes.

“We’re making a big, long-term bet on a shift in the industry,” Marshall says.