WS-PGRADE/gUSE and Clouds - Science Gateways for Distributed Computing Infrastructures - page 104

3. Any files used by the job are removed from the CBP, and thus from the cloud

storage as well.
4. The output

files are uploaded to their speci ed target URL (in case of jobs

submitted from WS-PGRADE, this is the file storage service of gUSE) as

written in the JSDL document.
5. Finally, DCI Bridge queries and records the costs of the job so they can be
presented later for the users through the web interface.

Beside the above, the CBP plugin of DCI Bridge is able to resubmit the failed
jobs at most as many times as speci s administration interface

for the plugin. Job resubmission is performed in the following cases: if the job

ed in the DCI Bridge '

' s

exit status is not zero or if any of the output files is missing. Job aborts are

performed with the help of the CBP Java API as well. Once a job has been
cancelled, all of its files are removed from the cloud storage and from the CBP ' s

registry as well.

7.5 Integration Features

The integrated WS-PGRADE/gUSE and CBP architecture offers easy access to
cloud infrastructures from scientific workflows. Thanks to the use of CBP, every
cloud infrastructure supported by CBP is available for use by WS-PGRADE/gUSE
users. This includes cloud infrastructures based on OpenNebula or OpenStack, and
Eucalyptus, Amazon, and IBM clouds. As can be seen, not only academic (usually
built on OpenNebula and OpenStack), but also commercial clouds are supported as
well. In this latter case, if access to the cloud infrastructure is not free of charge, the
extended set of WS-PGRADE portlets are capable of displaying a cost estimate
before, and the actual costs occurred after the jobs

' and workflows ' execution. This

is very important in commercial environments.
The integration completely supports the SaaS concept offered by the CBP. As
presented earlier, WS-PGRADE/gUSE users can select from the available set of
software applications deployed on the CBP for execution. Additionally to the SaaS
concept, the integrated solution offers an IaaS-like operation mode as well (given that
an appropriate wrapper software is deployed on the CBP), with whichWS-PGRADE/
gUSE users can run their own applications in the available cloud infrastructures. This
feature provides a convenient way to test workflows during their development phase;
once the workflow is ready, the included applications can be deployed on the cloud
infrastructures and accessed following the SaaS concept.
Finally, all the customization features of WS-PGRADE/gUSE can exploit the
integration features as well: both the Remote API and the ASM API can be used
together with the CloudBroker Platform integration. Additionally, the robot cre-
dential concept is also supported by the integration. These enable the exploitation of
cloud infrastructures for real e-scientists in a transparent way.