Containers offer a lightweight model for quick deployment of applications in cloud-based infrastructures, based on small, modular and transient services. Several companies in IT industry adopt this mode of deployment instead of hypervisor-based infrastructures for different reasons: container images are portable in any locations without the need of being modified, containers offer near-native performance and permit a high degree of scalability. Despite the numerous advantages, containerization technology raises different security concerns. In this regard, the most alarming factor is the minor layer of isolation between instances compared with hypervisor-based solutions. In this sense, the first barrier against several attacks is a container configured according to the most recent security best practices.