17.2 Grid Scheduling

17.2.1 Grid Scheduling Overview

Maui can participate in a grid environment providing functionality and information critical to effective grid scheduling. Maui can provide information to grid schedulers about what resources are available, how much the resources cost, and when remote jobs can run. Maui also provides resource reservation and job staging facilities to allow grid scheduling systems integrated support with Maui facilities.

Currently, the Silver Grid Scheduler is the most advanced grid scheduler taking advantage of these capabilities. It provides automated data staging, account and allocation management, and resource reservation optimizations. It provides an intuitive interface for job submission and job management, using submission languages from popular resource management systems. The the Silver Home Page for more information.

17.2.2 Configuring Maui to Inter-Operate with Grid Schedulers

To utilize cluster scheduler facilities, the grid scheduler must be authenticated and authorized. Grid scheduler authentication is enabled by adding an entry to the maui-private.cfg file as shown in the Interface Security section of appendix E. Once authentication is setup, the level of grid scheduler authorization is configured. In most cases, the grid scheduler is assigned the role of a level 1 admin using the ADMIN1 parameter.

In most cases, not only must the grid scheduler be authenticated to Maui, but Maui must also be authenticated to the grid scheduler. In the case of Silver, this is accomplished by naming the instance of Maui by using the SCHEDCFG parameter and adding the shared secret key to silver's silver.cfg file.

17.2.3 Specifying Cluster Level Policies for Grid Jobs

The number and type of resources available for grid jobs can be constrained using policies and/or reservations. All grid workload is assigned the job attribute GRID. Reservations and policies can be configured to allow or deny access based on this attribute providing access to or exclusion from specific resources, limiting the quantity of grid jobs which can run at any given time, or constraining access to other special functions such as preemption.

17.2.4 Evaluating Performance Impact of Grid Workload

Maui integrates the grid jobs into the standard job queue and, unless specifically directed by special grid policies, treats grid jobs just like ordinary workload. In fact, aside from having the GRID job attribute set, grid jobs are identical to locally submitted workload. &nbps;When a grid job is received, Maui tracks two additional pieces of information. This information, System Id and System Job Id indicates the submitting grid scheduler and global job id respectively. To determine a job's global job id, the showq command can be run with the '-g' flag.

17.2.5 Diagnosing Grid Based Issues

To address various grid specific failures, Maui provides integrated diagnostic tools. Among the most useful is the diagnose -S command. This command provides information about the status of required grid management modules and the status of grid scheduler interface. In addition, it also reports on any grid level failures or discrepancies it locates.