docker

Docker is an open-source platform that automates the deployment, scaling, and management of applications using containerization. It allows developers and system administrators to package an application, along with all of its dependencies and configurations, into a standardized container image.

This container can then be run consistently across different environments, from development to production, without concern for underlying infrastructure differences. For network engineers, Docker is useful because sometimes network device images are available as Docker images.  Also, there are useful applications in Docker containers for network management, configuration, etc.