\abstractenglish{ % skip indentation just for this paragraph \textenglish{ \noindent Today, more and more people rely on IaaS (Infrastructure as a Service) services over a traditional on-premise infrastructure to provide computational support to applications, services and business processes. This is due to the fact that the costs of an organization or business are reduced, since there is no need for an upfront investment on the purchase of equipment. Also, the operational cost of using IaaS services is based on flexible billing models according to the usage (of the offered infrastructure resources). In addition, it is possible to scale the offered remote infrastructure, depending on the needs of the organization and the current workload of the services and applications to be supported. In this way, the responsibility for the equipment and its maintenance is transferred to third parties, while at the same time a new trust model is introduced between the user/organization and the cloud provider. The increased interest shown by enterprises when in comes to virtualization technologies (which are a key foundation of IaaS services) in conjunction with the rapid rise in popularity of container technologies such as Docker, has in turn begun to drive the adoption of the microservices architecture for application development. An architecture based on virtualization technologies for hosting applications in cloud infrastructures and container technologies for partitioning their functions into a set of containers and thus, providing an appropriate level of performance and scalability \cite{awsMicroservices}. However, such applications remain vulnerable to security issues that may be tied to the cloud and/or the technologies on which it is based. } \clearpage \textenglish{ In this thesis we will first analyze the security issues related to the cloud and in particular, those related to virtualization and container technologies. Then, we will analyze how these two technologies can be used in a more secure manner. However, the purpose of this thesis goes beyond that and moves to a more practical level by proposing the solution of a tool that can implement the proposed safe use of these technologies. In particular, this tool can not only create virtual machines across multiple cloud providers but also harden them in an automated manner. In addition, it is capable of installing the Docker container engine on these virtual machines, which it can also harden. The main goal of this work is to make it easier for an organization to install and configure in an automated manner a secure, distributed environment for the deployment and operation of a microservices application. This automation lies in the correct configuration of our tool, which does not require any special knowledge on technical or security issues concerning the infrastructure and operating systems. } \vskip 60pt \textenglish{ \noindent \textbf{Keywords:} Cloud, Security, Virtualization, Virtual Machines, Containers, Container Engine, Micro-services, Automation, Hardening } } \clearpage % Abstract ended, start a new page