TOWARDS DEPENDABLE GRIDS

To date, grids (a form of distributed system) have been used to aggregate resources for performance-starved applications typically resulting from scientific enquiry. Grids should not just be facilitating advances in science and engineering; rather they should also be making an impact on our daily lives by enabling sophisticated applications such as new consumer services and support for homeland defense. For example, grids providing financial services should be seamlessly interconnected with grids that support telecommunications, and grids providing health care services should be seamlessly interconnected with both financial services and telecommunications. This is not possible today because the poor grid dependability—which is tolerated by scientific users—would be unacceptable in critical infrastructure applications. This project aims at correcting this problem by developing technology that will allow grids to be used to provide services upon which society can depend. Grids must be engineered both to achieve high dependability and to permit assurance that high dependability has been achieved. 1 BACKGROUND AND MOTIVATION To date, grids have been designed to aggregate resources for performance-starved applications. The goals are easy-to-use remote execution, easy-to-use access to large data sets, single sign on, etc. The prototypical user needs to execute an MPI application, perhaps for particle physics, molecular dynamics, and weather forecasting, and perhaps without caring where it executes. Or maybe the user needs to execute 1000 jobs on idle desktops. These goals are the basis of emerging grids such as GEON, LEAD, iVDGL, NEES, TeraGrid, and others. The community is doing an excellent job of providing these capabilities via software such as the NSF Middleware Initiative (NMI) software, VDT, and the NPACKage software packages. Grids should not be facilitating just “Big Science”; rather they should be making an impact on our daily lives by enabling sophisticated applications such as new consumer services and support for homeland defense. This is simply not possible today because the goals and requirements are different. Current largescale scientific endeavors are able to depend on the grid because scientific users are largely tolerant of the grid’s: (1) often idiosyncratic behaviors; (2) unexplained or obtuse failures; and (3) inability to provide a highly available cyber infrastructure. Current grid systems provide services that are important to society, but our dependence will grow considerably over time reaching a point where they will become interwoven within the fabric of society. They will then have become critical infrastructure. Grid systems are dependent upon one another and will become more so. Grids providing financial services, for example, will depend on grids that support telecommunications, and grids providing health care services will depend on both financial services and telecommunications. The common need throughout all the various interdependent grid user communities is high levels of dependability; users must be able to depend upon the service they receive. This dependability will include reliability in some cases, availability in others, data integrity and confidentiality (security) in essentially all services, and possibly safety in some circumstances. There are many threats to dependable services, for example: (1) failure of a power system leading to power loss; (2) physical damage to the grid computing fabric as a result of natural events (hurricanes) or