Integrating a dynamic data federation into the ATLAS distributed data management system

Input data for applications that run in cloud computing centres can be stored at remote repositories, typically with multiple copies of the most 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. In this approach, the closest copy of the data is used based on geographical or other information. Currently, we are using the dynamic data federation, Dynafed, a software solution developed by CERN IT. Dynafed supports several industry standard interfaces, such as Amazon S3, Microsoft Azure and HTTP with WebDAV extensions. 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 set up an instance of Dynafed and integrated it into the ATLAS distributed data management system, Rucio. We report on the challenges faced during the installation and integration.