The article analyzes the current state of cloud services industry and in particular NaaS services. It’s defined common requirements for IT - systems with NaaS services. Tasks related to assessment of availability and reliability indicators of cloud infrastructures are discussed. Some recommendations to improve reliability are described. The article examines the features and variety of contracts between users and providers of cloud services. A model of a virtual NaaS network reliability assessment is analyzed. Using this model reliability indicators for cloud IT system with a virtual topology are calculated and researched.
cloud services, NaaS, availability, reliability, SLA