Utility computing

Utility computing has sparked imaginations with visions of pay-as-you-go billing, and dynamic resources for years. The concept is simple; rather than operating servers, businesses subscribe to a utility computing service and pay for the resources they actually use. Despite significant R&D investments, though, most vendor offerings fall far short of these ideals. Utility computing, it turns out, has been far harder to realize than the pundits predicted.

The Challenge

The primary obstacle to true utility computing is the structure of modern online applications. These are complex systems comprised of the application software itself, middleware software like web servers and databases, operating systems and drivers, numerous servers, storage to boot the servers, storage to hold the application data, and finally the networks that connect it all. Simply deploying and operating these systems requires significant expertise. Simplifying applications requires eliminating the interlocking bindings between the components in the system. The traditional approach has been to build templates to map the dependencies automate updates when changes are made. Unfortunately, this is a brittle solution requiring significant maintenance of its own. Attempting to remote applications to utility providers in this complex state isn't utility computing; it's contract services.

3Tera's Solution

3Tera's AppLogic grid operating system eliminates the binding of software to hardware through virtualization. Applications are assembled using completely self-contained software components called virtual appliances. When run, the software in the virtual appliance operates in a completely virtualized execution space consisting of a virtual machine and virtualized access to storage and networks. Almost any piece of Linux software can be made into a virtual appliance in about the same time it takes to install it on a server without code changes.

When virtual appliances aren't running, they consume no processing resources and only a small amount of storage. As such, rather than using them sparingly as traditional software is, virtual appliances can be packaged with every application that uses them. In essence, the virtual appliances form a disposable infrastructure on which the application relies while operating. When the application is run, the virtual infrastructure it requires is created dynamically on the grid, maintained while it runs, and disposed of when it stops.

The use of virtual appliances makes applications scalable within AppLogic as well. Each virtual appliance has a range of resource usage over which it produces valuable output. The actual resources used in production are only assigned at runtime. For instance, a web server virtual appliance may require 5% of a CPU and 64MB of RAM to respond to a query and may stop providing greater output at 50% of a CPU and 1GB of memory. A two-tier application that includes this virtual appliance in addition to five or six other virtual appliances, may run with as little as 25% of a CPU and 300MB RAM, but still be able to scale to more than 3 servers and 6GB of memory.

Solution Benefits

AppLogic enables utility computing by making applications completely self-contained, scalable and portable. They have no dependence on specific hardware of any kind. Therefore, they can be copied and run on any AppLogic grid without modification. Exactly how much resource is assigned to each instance of the application depends on the users' needs at runtime.