RancherOS is a small operating system of only about 20MB in size, with only the basics to function, it does not stop having a multitude of functionalities. Designed to work on Docker, another of the projects that promise a lot and are giving a lot to talk about lately. RancherOS is managed by Docker, both the services of the system itself such as udev, rsyslog, etc.
RancherOS runs everything through containers thanks to the Docker project. The design of RancherOS makes PID 1 take care of calling DOcker and starting it, this in turn calls "User Docker", which is simply a system to run containers, allowing any user to erase the entire operating system ("System Docker '). For those who do not know what Docker and containers are, I invite you to investigate a little, it is very interesting in terms of virtualization.
How could it be otherwise, RancherOS is an innovative project based on a Linux kernel. The distro is already on version 0.4.2 and uses Docker 1.9.1, with a kernel higher than Linux 4.2 version. That is, despite its small size, it does not use a very primitive kernel, but is a very current version. This combination has made this project especially practical to build any type of infrastructure.
For those who still do not know what is that of the containers (isolated guests running as an app on top of the host) or the Docker project, saying it's possibly the future of virtualization. Docker only works under Linux and is an open source project for deploying applications within software containers, providing a layer of abstraction and automation of virtualization at the operating system level. This avoids the overhead of starting and maintaining virtual machines as in conventional virtualization.
If you are interested, you can access the official website - www.rancher.com/rancher-os/