VM-based infrastructure for simulating different cluster and storage solutions used on ATLAS Tier-3 sites

Abstract

The current ATLAS Tier-3 infrastructure consists of a variety of sites of different sizes and with a mix of local resource management systems (LRMS) and mass storage system (MSS) implementations. The Tier-3 monitoring suite, having been developed in order to satisfy the needs of Tier-3 site administrators and to aggregate Tier-3 monitoring information on the global VO level, needs to be validated for various combinations of LRMS and MSS solutions along with the corresponding Ganglia plugins. For this purpose the testbed infrastructure, which allows simulation of various computational cluster and storage solutions, had been set up at JINR (Dubna, Russia). This infrastructure provides the ability to run testbeds with various LRMS and MSS implementations, and with the capability to quickly redeploy particular testbeds or their components. Performance of specific components is not a critical issue for development and validation, whereas easy management and deployment are crucial. Therefore virtual machines were chosen for implementation of the validation infrastructure which, though initially developed for Tier-3 monitoring project, can be exploited for other purposes. Load generators for simulation of the computing activities at the farm were developed as a part of this task. The paper will cover concrete implementation, including deployment scenarios, hypervisor details and load simulators.