The emerging Containers as a Service (CaaS) space is seeing a lot of movement and provides a useful option between basic IaaS (Infrastructure as a Service) and more opinionated PaaS (Platform as a Service). While Rancher creates less noise than some other players, we have enjoyed the simplicity that it brings to running Docker containers in production. It can run stand-alone as a full solution or in conjunction with tools like Kubernetes.
Rancher is an open source solution that allows deployment of containers into a cluster of machines, which is becoming an increasingly common scenario. It provides services such lifecycle management, monitoring, health checks and discovery. Also included is a completely containerized operating system based on Docker. The broad focus on containerization and very small footprint are key advantages for Rancher. A similar solution in this space is Kubernetes.