Resource Selection – Brokering with ARC
Mattias Ellert
Uppsala University

NorduGrid Special Event Track

European Grid Conference

Amsterdam 2005-02-15

ngsub

The command line tool that is used for submitting jobs – ngsub – is also responsible for selecting the appropriate resource to send the job to

No centralized broker – avoiding a single point of failure

Resource Discovery

The brokering starts from a list of available resources obtained from the information system

From this list a set of possible submission targets that can process the job is extracted

Is the user authorized at the resource?

Does the resource match the criteria specified in the job description (number of CPUs, requested CPU time, memory, architecture, runtime environments, network connectivity etc.)?

Resource Selection

From the set of possible targets one resource is selected taking into account among other things:

The amount of input data that is locally available at the resource

The number of free CPU at the resource

The number of queued jobs at the resource

Fine Tuning

Several options exists that the user can use to fine tune the behaviour of the broker, e.g.

The default behaviour is to send a job to a resource where the input files are locally available if possible – but if all such resources are occupied and there are free resources elsewhere the job is sent to a free resource and stages the input files from the remote storage. By specifying the local option (for one or more input files) the brokering will only consider resources where the input is locally available

2005-02-12T02:08:03