Information Technology Reference
In-Depth Information
5.2 Architecture
The primary components of the workl ow enactment engine (WFEE) [5]
and their relationship with other services in the grid infrastructure are
shown in Figure 5.1. Workl ow applications, such as scientii c application
portals, submit task dei nitions along with their dependencies, expressed
in a workl ow language, as well as associated QoS requirements to WFEE.
WFEE schedules tasks through grid middleware on the grid resources.
The key components of WFEE are workl ow submission, workl ow lan-
guage parser, resource discovery, dispatcher, data movement, and work-
l ow scheduler.
•
Workl ow submission accepts workl ow enactment requests from
planner level applications.
Workl ow language parser converts workl ow description from
•
XML format into Java objects,
Task
,
Parameter
, and
DataConstraint
(workl ow dependency), which can be accessed by workl ow
scheduler.
Resource discovery is carried out by querying grid information
•
services such as Globus MDS [6], directory services, and replica
catalogs to locate suitable resources for the tasks.
……
Workflow planner
Application composition
Scientific portal
Workflow description & QoS
Workflow
Enactment engine
Info service
Workflow submission handler
Workflow language parser
GMD
Resource discovery
Parameters
Tasks
Dependencies
Replica
catalog
Workflow scheduler
MDS
Dispatcher
Data movement
Gridbus broker
Web services
Globus
HTTP
GridFTP
Database
Database
FIGURE 5.1
Architecture of WFEE.
Search WWH ::
Custom Search