rPath's rBuilder 5 Streamlines Linux Virtual Machine Management

rPath maintains its own Linux distribution, rPath Linux, from which rBuilder can pluck the components required to build software appliances. rPath Linux is a fairly conservative distribution that's capable of serving most Linux applications without issue.

However, for applications designed or certified to work on a specific distribution, using rPath's own Linux can pose support hurdles. It's in these cases that rBuilder's support for Linux distributions beyond rPath Linux comes in handy. rBuilder offers the choice of SUSE Linux Enterprise Server 10 or 11, Ubuntu Hardy or the Red Hat Enterprise Linux 5 clone, CentOS 5. For the SLES options, you must configure rBuilder with an activation key confirming that you're entitled to run the distribution.

When I embarked on my appliance-creation journey, rBuilder prompted me to choose one of these distributions. Later, I could easily switch platforms through the product's Flash-based interface. I switched appliances from rPath Linux 2 to CentOS and vice versa.

Virtualization Target Support

Also new in the 5.x versions of rBuilder is a management console through which I could configure virtualization host targets to link up with rBuilder. I could choose from on-premises VMware ESX Server or Citrix XenServer hosts, or the cloud-based Amazon EC2 or the Globus Workspaces Cloud. I tested with a VMware vSphere installation and with an Amazon EC2 account. In both cases, I could see a list of the running instances on the services, as well as launch or terminate new instances from rBuilder.

I could also create virtual images in a fairly comprehensive range of other formats, including those for Microsoft Hyper-V, Virtual Iron, Parallels, QEMU, installable DVD or CD ISOs and plain TAR archives.

Flash-based Interface

Among the most striking changes between the 4.x and 5.x versions of rBuilder is a move from an HTML and Javascript-based Web interface to a new Web front end built on Adobe's Flash framework. The Flash interface gives rBuilder a look and feel more akin to a regular desktop application, while retaining the cross-platform support of the HTML interface.

Overall, my experience with the new interface was positive. In my first experiences with the new UI, just after Version 5 became available, I was tempted to say that rPath had pushed the envelope a bit too far in terms of what’s feasible with a Flash-based application, but the company has managed to iron out most of the early wrinkles I encountered.

For example, while testing earlier 5.x builds of rBuilder, I experienced some performance issues with the Flash-based interface, which tended to result in my browser--and all its open tabs--locking up for short periods of time. Specifically, I experienced these problems while connecting to VMware ESX server targets. With Version 5.2.1 of rBuilder, those particular lockup issues seemed to have been ironed out.

However, there were some Flash issues even in Version 5.2.1. In one case, I triggered a build of one of my appliance images, but the operation wasn't reflected in the interface. I clicked a couple more times to launch the build, but it wasn't until I refreshed the page that I could see that each of my clicks had indeed added a new build process to the product's queue. The interface offered no option to cancel the redundant operations, so I had to either wait for them to finish or visit a separate rBuilder administration console to cancel them.

Executive Editor Jason Brooks can be reached at jbrooks@eweek.com.