Virtualization has been dominating the world on the aspect of software development and testing for quite some time. Nowadays, Containerization and Docker in particular have become the new trend of developing software due to its simplicity, portability, scalability and it requires less resources than a Virtual Machine. It has to be mentioned though, that despite the advantages of Docker, there are some problems regarding security that need to be addressed. In this thesis, we will analyze Virtualization and Containerization along with their advantages. We will also examine the Docker architecture and functionality through some use cases. Furthermore static and dynamic analysis of Docker images and containers will be presented through the usage of certain tools. In addition, Docker forensics will be analyzed and tested through a use case. Lastly, there will be a thorough description of best practices regarding the Docker environment.