OurGrid is an opensourcegridmiddleware based on a peer-to-peer architecture. OurGrid was mainly developed at the Federal University of Campina Grande, which has run an OurGrid instance named "OurGrid" since December 2004. Anyone can freely and easily join it to gain access to large amount of computational power and run parallel applications. This computational power is provided by the idle resources of all participants, and is shared in a way that makes those who contribute more get more when they need. Currently, the platform can be used to run any application whose tasks do not communicate among themselves during execution, like most simulations, data mining and searching.
The OurGrid Broker is the scheduling component of the OurGrid solution. A machine running the Broker is called the home machine, which is the central point of a grid. During the processing of jobs, it acts as the grid coordinator, scheduling the execution of tasks and doing all the necessary data transfer to and from grid machines. Due to its central role, grid configuration and management, as well as job specification, is done on the home machine. The Broker is OurGrid's user frontend. It provides support to describe, execute, and monitor jobs. Job processing is done by machines running OurGrid Workers. During the execution of a job, the Broker gets Workers on-demand from its associated Peer. It is the Broker's role to schedule the tasks to run on the Workers and to deploy and retrieve all data to/from Workers before and after the execution of tasks.
Peers
An OurGrid Peer runs on a machine called the peer machine. The main role of a Peer is to organize and provide worker machines that belong to the same administrative domain. From the user's perspective, a Peer is a Worker provider, i.e., a network service that dynamically provides Workers for task execution. From an administrative point of view, a Peer determines how and which machines can be used as workers.
Workers
The OurGrid Worker component runs on each machine that will be available for task execution. The Worker provides necessary access functionality to the home machine. It also provides some basic support for instrumentation and fault handling. Furthermore, combined with the OurGrid Peer, it allows for the use of machines in private networks. In practice, any computer connected to the Internet can be used as a worker machine, even if it lies in a different administrative domain or behind a firewall. In Figure 1.1, administrative domains, possibly using their own intranets, are illustrated as rectangles containing Workers.
Network of Favours
To encourage resource contribution to the network, OurGrid uses a resource allocation mechanism called Network of Favours. The Network of Favours is an autonomous reputation scheme that rewards Peers that contribute more. This way, there is an incentive for each Peer to contribute as much as possible to the system. The OurGrid Community is a peer-to-peer resource sharing system focused on providing resources to BoT applications. The central mission of OurGrid Community is that the sharing be done using the network of favours model. In this model, each Peer offers access to its idle resources to the community. In return, when there is work that exceeds local capacity, a Peer expects to gain access to the idle resources of other participants. The system aims to allow users of BoT applications to easily obtain access and use the community's computational resources, dynamically forming an on-demand, large-scale, grid. Each Peer in the community is an entity that owns a number of resources and occasionally needs more computing power than these resources can provide. Whenever a Peer needs more power, it requests resources to the community. Whenever it has idle resources, it allocates them to one of the requesters. As there are no guarantees about the quality of service obtained from the idle resources donated to the community, not all applications are suitable for OurGrid.
