Runtime System

The AppLogic Runtime System includes the following major subsystems:

• Distributed Kernel
• Disposable Infrastructure Manager
• Grid Controller

Distributed Kernel

The AppLogic Distributed Kernel provides a set of system services required to implement the distributed infrastructure and application model of AppLogic. The three most important system services include the Global Volume Store, the Distributed Virtual Machine Manager and the Logical Connection Manager. Together, these services abstract the distributed nature of the underlying grid, virtualize its hardware resources, and provide the runtime abstractions necessary to implement the rest of AppLogic.

Global Volume Store (GVS)

GVS implements a new type of distributed storage subsystem that combines the advantages of a global file system with an object store. The key object supported by GVS is a virtual volume. Virtual volumes exist in a hierarchical namespace, can be created, destroyed and cloned on demand, and are mirrored on multiple servers for read performance and availability.

GVS scales linearly to hundreds of servers in both performance and capacity. Due to advanced caching and network access algorithms, GVS volumes are generally 10-15% faster than local physical disks. In addition, GVS supports the ability to take snapshots of a volume or a set of volumes, which makes it easy to backup entire applications.

Distributed Virtual Machine Manager (DVM)

The AppLogic distributed virtual machine manager is built on top of the Xen hypervisor, the leading open source server virtualization technology. DVM extends Xen with grid-specific functionality and provides ability to create a virtual machine anywhere on the grid, guarantee hardware resource assignment for each VM and schedule sets of virtual machines across the grid.

Logical Connection Manager (LCM)

The logical connection manager abstracts intercomponent communications. It enables AppLogic to define all interactions between components of an application in terms of point-to-point logical connections between virtual appliances. The interactions are controlled and tunneled across physical networks, allowing AppLogic to enforce interaction protocols, detect security breaches and migrate live TCP connections from one IP network to another transparently.

Disposable Infrastructure Manager

The disposable infrastructure manager handles the infrastructure for each Applogic application which includes the following:

• Virtual Appliances
• Assemblies
• Catalogs
• Applications

Virtual Appliances

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.

Assemblies

An AppLogic assembly is a packaged structure of interconnected components that can be manufactured on demand and used in exactly the same way as one would use a virtual appliance. The assembly support is hierarchical, allowing users to create assemblies of assemblies of assemblies and so on.

Catalogs

An AppLogic catalog is a set of disposable infrastructure appliances, such as gateways, firewalls, load balancers, web servers, application servers, database servers, file servers, mail servers and so on. The main assembly of an application ties them together into a logical structure capable of running the application. This includes all information required to configure each appliance and tie them together

Applications

An AppLogic application is a single system object that includes everything necessary to run a specific distributed application such as a CRM system, a PBX or an e-commerce application. It includes the application code, HTML pages, templates and scripts, databases and content, but also operating systems, middleware, file storage, load balancers, firewalls and all configuration information needed to reconstruct and run the application on an AppLogic grid. In addition, each application carries a defined resource budget - a minimum set of hardware resources including CPU, memory and bandwidth that are required to run the application, and the maximum resource quota allowed for it.

Grid Controller

The grid controller provides a point for managing and monitoring the grid. The grid controller provides the following services:

• User Interface
• Grid Management
• Application Manaagement

User Interface

The primary user interface of AppLogic is visual, and delivered via a browser. The visual interface is AJAX-based and is highly interactive, with the look and feel of a desktop application. In addition, all system functions are also available through the command line interface.

The AppLogic User Interface consists of the following major components:

• System dashboard
• Infrastructure editor
• Command-line interface

Grid Management

The grid management system provides the ability to manage all of the servers of a grid as a single system. Information about the grid may be viewed via the System Dashboard. The grid may be managed via the Grid Control commands and Server Management commands provided by the Command Line Interface.

Application Management

Many of the application management activities can be performed via both the application editor and the command line. However, some activities are only available via the command line such as start, stop, provision, migrate, and retrieving detailed information about the application (e.g., current state, list of components, etc.).