Documentation

What is cOS?

cOS is a toolkit which allows container images to be bootable in VMs, baremetals, embedded devices, and much more.

cOS allows to create meta-Linux derivatives which are configured throughout cloud-init configuration files and are immutable by default.

cOS and derivatives shares a common feature set, can be upgraded in a OTA-alike* style, and upgrades are delivered with standard container registries.

cOS comes also with vanilla images that can be used to boot directly container images built with the toolkit.

Why cOS?

cOS allows to create custom OS versions in your cluster with standard container images with a high degree of customization. It can also be used in its vanilla form - cOS enables then everyone to build their own derivative and access it in various formats.

To build a bootable image is as simple as running docker build.

• What is it good for?: Embedded, Cloud, Containers, VM, Baremetals, Servers, IoT, Edge

Design goals

• A Manifest for container-based OS. It contains just the common bits to make a container image bootable and to be upgraded from, with few customization on top
• Everything is an OCI artifact from the ground-up
• Immutable-first, but with a flexible layout
• Cloud-init driven
• Based on systemd
• Built and upgraded from containers - It is a single image OS!
• OTA updates
• Easy to customize
• Cryptographically verified
• instant switch from different versions
• recovery mechanism with cOS vanilla images (or bring your own)

Mission

The cOS-toolkit project is under the Elemental umbrella.

Elemental provides a unique container based approach to define the system lifecycle of an immutable Linux derivative, without any string attached to a specific Linux distribution.

At its heart, Elemental is the abstraction layer between Linux distro management and the specific purpose of the OS.

Elemental empowers anyone to create derivatives from standard OCI images. Frees whoever wants to create a Linux derivative from handling the heavy bits of packaging and managing entire repositories to propagate upgrades, simplifying the entire process by using container images as base for OS. At the same time, Elemental provides an highly integrated ecosystem which is designed to be container-first, cloud native, and immutable. Anyone can tweak Elemental derivatives from the bottom-up to enable and disable its featureset.

As the Elemental team, the os2 project is our point of reference.

os2 is a complete derivative built with Elemental tied with the rancher ecosystem and full cycle node management solution with Kubernetes.

We are supporting directly and indirectly os2 within changes also in the Elemental ecosystem.

os2 is our main show-case, and as the Elemental team we are committed to it. It encompasses several technologies to create a Kubernetes-focused Linux derivative which lifecycle is managed entirely from Kubernetes itself, Secure Device Onboarding included, and automatic provisioning via cloud-init.