DARGOS: A highly adaptable and scalable monitoring architecture for multi-tenant Clouds

One of the most important features in Cloud environments is to know the status and the availability of the physical resources and services present in the current infrastructure. A full knowledge and control of the current status of those resources enables Cloud administrators to design better Cloud provisioning strategies and to avoid SLA violations. However, it is not easy to manage such information in a reliable and scalable way, especially when we consider Cloud environments used and shared by several tenants and when we need to harmonize their different monitoring needs at different Cloud software stack layers. To cope with these issues, we propose Distributed Architecture for Resource manaGement and mOnitoring in cloudS (DARGOS), a completely distributed and highly efficient Cloud monitoring architecture to disseminate resource monitoring information. DARGOS ensures an accurate measurement of physical and virtual resources in the Cloud keeping at the same time a low overhead. In addition, DARGOS is flexible and adaptable and allows defining and monitoring new metrics easily. The proposed monitoring architecture and related tools have been integrated into a real Cloud deployment based on the OpenStack platform: they are openly available for the research community and include a Web-based customizable Cloud monitoring console. We report experimental results to assess our architecture and quantitatively compare it with a selection of other Cloud monitoring systems similar to ours showing that DARGOS introduces a very limited and scalable monitoring overhead.