The paper is devoted to the problem of studying the Linux operating system (OS) by future computer science teachers. The authors have developed a learning tool - the cloud lab (CL-OS). Based on an analysis of related research, they concluded that a cloud lab is a system that uses cloud computing technology to provide the desired user interface to access computing resources. The authors have systematized some experience of using mass open online courses (MOOC) and remote access laboratories. They made assumptions about the possibility and necessity of creating cloud laboratories in universities and colleges. This article described the experience of deploying an authors` cloud laboratory. It is based on integrating the NDG Linux Essentials course from Cisco NetAcad and the Apache CloudStack cloud platform. The authors have analyzed the specifics of training under the conditions of using their cloud laboratory. In particular, some limitations and problems of students' work under the conditions of the real educational process (both face-to-face and online) were identified. A pedagogical experiment was conducted to confirm the effectiveness of the author's approaches. Its results were verified using statistical methods.