Science Gateway for the Serbian Condensed Matter Physics Community - Science Gateways for Distributed Computing Infrastructures - page 204

workflow submission engine (WSE) daemon process looks for con gurations

waiting for the executions, and performs application-speci c workflow submission

through the WS-PGRADE/gUSE Remote API interface. The portal was developed
within the Google Web Toolkit (Tacy 2013) environment using Bootstrap (Cochran
2012) front-end framework, and it was deployed through the Apache Tomcat
(Brittain 2007) server (available at: http://sci-bus.ipb.ac.rs/ ) .
The WS-PGRADE/gUSE Portal is a workflow developer-oriented interface based
on the WS-PGRADE/gUSE technology. It allows creation of new workflows,
modi

cation of existing ones, and manual testing. Use of the portal requires a Lif-
eray-based (Liferay 2014) account, a valid digital certi cate and membership in

cmpc.aegis.rs VO. Potential users are able to request Liferay-based account by lling

out the generic Liferay Create Account form available at home page of AEGIS
CMPC SG. The National Grid Initiative (NGI) AEGIS VOMS-admin portal provides
management of cmpc.aegis.rs VO membership. The membership request form of the
VOMS-admin portal requires a digital certi

cate, and therefore, in order to fill it out, a

workflow developer has to import a personal certi cate into the web browser. The

AEGIS WS-PGRADE/gUSE Portal extends the default WS-PGRADE/gUSE
installation with the Remote API plugin that enables usage of the core gUSE services
without the WS-PGRADE user interface component. The Remote API allows one
to run and manage workflows from a custom user interface, such as the AEGIS
CMPC Portal.
Workflows of AEGIS CMPC applications are created within the WS-PGRADE/
gUSE Portal, and are exposed for the external usage through the Remote API
component. Since SPEEDUP and QSPEEDUP applications use identical algo-
rithms, just supplied with different random number generators, both applications
use a single workflow

a (Q)SPEEDUP workflow. In order to minimize the net-
work overhead, all application binaries are preinstalled on each of DCI resource
centers supporting the cmpc.aegis.rs VO. The VO software area is used for this
purpose, while the installation and upgrade of particular applications is performed
by VO managers.
The workflow behind the (Q)SPEEDUP application is illustrated in Fig 15.3 .It
has three main components:

—

(Q)SPEEDUP-PREPARATION retrieves user-de gu-

rations from the database. Retrieved JSON output is then converted to the
application-speci

ned physical system con

￿

file, which is forwarded to the next process in
the workflow. Together with the con

c con guration

file, technical metadata (consumed
CPU time, application version, random number generator stream, etc.) produced
in this part of the workflow are forwarded to the next process. This is not a CPU-
intensive task, and it is executed at the server that hosts the WS-PGRADE/gUSE
portal (localhost).

guration

￿ (Q)SPEEDUP-EXECUTION is responsible for the application execution at the

DCI, and then it retrieves the results. It equips the application with the wrapper that
is able to determine the location of the preinstalled application at the DCI, sup-
ply input parameters, initiate execution, and collect results. This CPU-intensive