RancherOS is a lightweight Linux operating system distribution that includes only the necessary libraries and services to deploy and scale containers. RancherOS is an open source project run by Rancher Labs.
This Linux OS containerizes system services to use Docker for management and create a container-ready environment. Everything within RancherOS is a Docker container. It consists of nothing more than the Linux kernel that runs the Docker daemon. The System Docker daemon is where RancherOS runs system services. This keeps the RancherOS components run within containers separate from the user's containers.
An IT pro can deploy RancherOS either as a container image or a standalone server, or as a VM generated from an ISO image. The OS requires 512MB of RAM to install. ISO images come in at just 57.7 MB and boot times are generally five to 10 seconds. The operating system is designed with the expectation that users package all necessary libraries for hosted applications in the containers running atop RancherOS.
Many companies use RancherOS, including Kloeckner & Co., LateRooms.com, Bit Space Development, United Electronics, Cloudsoar and BloomAPI.
RancherOS is one of the many operating systems designed or optimized for containers. Others include:
RancherOS is considered one of the barest of the bare-bones Linux systems that can run Docker containers at scale.
The RancherOS distribution is ideal for containers, in particular containers that will scale up and down, and those hosting app components broken apart into microservices. This is, effectively, a container within a container -- consider it little more than a single-minded system that efficiently and effectively runs only the docker command, but still offers a full ISO image.
Rancher Labs also produces Rancher, a container management product based on Kubernetes.