Docker is the most popular program that performs operating-level-system virtualization, also known as "containerization".
 

As a tool that can package an application and its dependencies in a virtual container, Docker enables flexibility and portability on where the application can run, whether on premises, public cloud, private cloud, bare metal...
 

Containers generated and ruled by Docker may simplify the creation of highly distributed systems by allowing multiple applications, worker tasks and other processes to run autonomously on a single physical machine or across multiple virtual machines. This allows the deployment of nodes to be performed as the resources become available or when more nodes are needed, allowing a platform as a service (PaaS)-style of deployment.