Disposable Infrastructure

The ability to make infrastructure on demand is a unique feature of AppLogic. Instant infrastructure is possible because the recent rapid growth in the performance of commodity x86 processors in comparison with the performance of network and storage hardware. These powerful CPUs make it possible to implement in software most of the infrastructure functions that needed hardware assistance even a couple of years ago. AppLogic to take the "smarts" out the smart infrastructure boxes and package them into software objects that are created on demand and composed into complete application infrastructures.

The technological foundation of AppLogic instant infrastructure is a new distributed component model. The AppLogic component model provides several powerful and unique capabilities:

• AppLogic runs existing software in components.
  An AppLogic component is called a virtual appliance. Unlike any other component model in existence, each instance of a virtual appliance executes in a completely virtualized environment, boots its own operating system, application services and other software. This enables AppLogic to package existing software into components that are easy to create on demand from a common class definition.
• AppLogic components are assembled visually. The AppLogic component model makes it possible to assemble structures of virtual appliances by configuring them and wiring them together in a browser. This makes it extremely easy to build custom infrastructure for N-tier applications, as well as to visually debug, monitor and operate such applications.
• AppLogic supports hierarchical composition. The AppLogic component model makes it possible to package structures of interconnected components into new appliance classes that can be produced on demand and used in exactly the same way as one would use a virtual appliance. For example, one can assemble a "clustered database appliance" from regular database servers, load balancers and storage, and make a complex cluster as easy to use as a single database appliance. The assembly support is hierarchical, allowing users to create assemblies of assemblies of assemblies and so on, enabling the construction of truly gigantic applications. Indeed, every AppLogic application is an assembly.

Figure 2. Manufacturing disposable infrastructure on demand.

Figure 2 illustrates the process of manufacturing infrastructure components on demand in AppLogic. A class definition, consisting of a class descriptor and one or more class volumes, defines a class of disposable virtual appliances, such as a web server, or a load balancer. The class volumes contain all of the software required to boot and operate an instance of this class, including an operating system (e.g. Linux), application services (e.g. Apache httpd) and anything else the appliance may need. The class descriptor defines the characteristics of the appliance as component, including its inputs, outputs, configuration properties and their default values, volumes, and hardware resources.

When requested, AppLogic produces a running instance of the appliance from the class definition by applying configuration information specific for that instance to the class definition. Each instance consists of a virtual machine, one or more virtual storage volumes and one or more virtual network interfaces. The software included in the instance executes in a completely virtualized environment, fully equivalent to running on a separate physical server. Network interactions are also virtualized, enabling a secure and flexible way to interconnect components.

This process makes it easy to create infrastructure on demand, custom for each application or even application instance, and tear it down when the need for it is no longer there.