Back in July, we looked at how cloud computing may force appliance vendors to change the way they build products. Now rPath, which makes release management tools for virtual appliances, is announcing support for EC2 on its rBuilder portal, a web site that lets users turn software into virtual appliances and publish them to clouds and virtual environments with a few clicks. It’s an impressive step in web-based release management for virtual environments, but rPath’s road may be bumpy.

Virtual appliances are bundles of software and “just enough operating system,” as rPath chief evangelist Marty Wesley puts it, to make them run. Software destined for an appliance comes in the form of distributions (such as Red Hat’s RPM format) that contain the code and related libraries. rPath’s tool first teases apart these distributions and identifies their components.

Armed with a list of what needs to go into the appliance, the tool then tailors it to the target cloud or virtual machine. “We grab the contents [of the distribution] and add them to a cart,” said Wesley. For example, if the appliance is destined for VMware, rPath adds code specific to that environment; for EC2, it leaves out the kernel and requests EC2 credentials. Finally, the system publishes the results to a variety of environments.

The Raleigh, N.C.-based startup is filled with Red Hat alumni, including CTO Erik Troan, who authored the Red Hat software packaging system RPM. rPath is seeing modest growth from its enterprise offering, claiming 58 customers since its launch in 2006, many of whom are large enterprises or ISVs who want to ship VM-ready versions of their software. The company has taken in a total of $25 million in funding, with a $15 million round completed this April, and has 25 engineers. Both CohesiveFT and FastScale are competitors, although they don’t support as many target environments; JumpBox, meanwhile, makes pre-built appliances for many popular applications.

But rPath is at a crossroads. If it wants to own the enterprise release management cycle, it needs more than just Linux RPM distributions. Here, Microsoft is just around the corner with its suite of virtualization, operating systems, and applications.

On the other hand, if rPath wants to focus on clouds with its catalog of appliances, it needs to move beyond individual machines and into scalable, multimachine application clusters. Wesley says the company is already pursuing this, but cloud management firms Elastra, 3Tera and Enomalism have a head start, offering management, scaling and licensing tools for virtual machines.

Whatever the bumps ahead, rPath’s portal and new EC2 support is a reminder of just how easily and quickly companies can move applications into an on-demand environment and free software from its underlying platform.

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