F. Berghaus

Dynamic web cache publishing for IaaS clouds using Shoal

We have developed a highly scalable application, called Shoal, for tracking and utilizing a distributed set of HTTP web caches. Squid servers advertise their existence to the Shoal server via AMQP messaging by running Shoal Agent. The Shoal server provides a simple REST interface that allows clients to determine their closest Squid cache. Our goal is to dynamically instantiate Squid caches on IaaS clouds in response to client demand. Shoal provides the VMs on IaaS clouds with the location of the nearest dynamically instantiated Squid Cache. In this paper, we describe the design and performance of Shoal.

Federating Distributed Storage For Clouds In ATLAS

Input data for applications that run in cloud computing centres can be stored at distant repositories, often with multiple copies of the popular data stored at many sites. Locating and retrieving the remote data can be challenging, and we believe that federating the storage can address this problem. A federation would locate the closest copy of the data on the basis of GeoIP information. Currently we are using the dynamic data federation Dynafed, a software solution developed by CERN IT. Dynafed supports several industry standards for connection protocols like Amazons S3, Microsofts Azure, as well as WebDAV and HTTP. Dynafed functions as an abstraction layer under which protocol-dependent authentication details are hidden from the user, requiring the user to only provide an X509 certificate. We have setup an instance of Dynafed and integrated it into the ATLAS data distribution management system. We report on the challenges faced during the installation and integration. We have tested ATLAS analysis jobs submitted by the PanDA production system and we report on our first experiences with its operation.

HEP computing in a context-aware cloud environment

This paper describes the use of a distributed cloud computing system for high energy physics (HEP) applications. The system is composed of IaaS clouds integrated into a unified infrastructure that has been in production for over two years. It continues to expand in scale and sites, encompassing more than twenty clouds on three continents. We are prototyping a new context-aware architecture that enables the virtual machines to make connections to both software and data repositories based on geolocation information. The new design will significantly enhance the ability of the system to scale to higher workloads and run data-intensive applications. We review the operation of the production system and describe our work towards a context-aware cloud system.