The manual covers fundamental principles, concepts, technologies and peculiarities of modern distributed systems functioning. Laboratory exercises are supplemented with theoretical materials and various practical examples.This textbook is intended for students as well as specialists in the field of information technologies. For its understanding it is enough to have initial information from the courses on operating systems, network technologies and programming. The content of the textbook meets the current requirements of the state educational standard of higher education. For students of higher educational institutions, studying in IT directions.