JINR cloud service: status and perspectives

Many large-scale cloud data centers have been deployed all over the world  and successfully function both in business and science. Currently many scientific organizations deploy their own private clouds moving their computations and IT services into them. Cloud technologies are actively developed and many scientific teams conduct research in the field of cloud environments structure. One of the main directions of research in cloud computing at the moment is research of methods for efficiency increase of computing resources. Development of cloud technologies led to the next stage of their evolution - integration of cloud computing environments. This imposes new requirements on used platforms as well as on basic principles and modes of operation of cloud environments integrally and raises a wide range of new problems and researches. The paper describes some basic topics and use cases of cloud computing environments in various scientific laboratories. It describes activities of the Joint Institute for Nuclear Research (JINR) aimed at the development of the cloud infrastructure (which is built completely on open-source components) deployed in the Laboratory of Information Technologies in JINR, as well as applied strategies of the improvement of efficiency, fault tolerance and reliability of the JINR cloud service, and also its integration with other cloud services.