Project Atomic is now sunset

The Atomic Host platform is now replaced by CoreOS. Users of Atomic Host are encouraged to join the CoreOS community on the Fedora CoreOS communication channels.

The documentation contained below and throughout this site has been retained for historical purposes, but can no longer be guaranteed to be accurate.

Introduction to Project Atomic

Project Atomic is an umbrella for many projects related to re-designing the operating system around principles of immutable infrastructure, using the LDK (Linux, Docker, Kubernetes) stack.

Many of the components of Project Atomic are upstream components of OpenShift Origin v3.

The primary building block of Project Atomic is the Atomic Host, a lightweight container OS which implements these ideas. Atomic Hosts are immutable, since each is imaged from an upstream repository, supporting mass deployment. Applications run in containers. Atomic Host versions based on CentOS and Fedora are available, and there is also a downstream enterprise version in Red Hat Enterprise Linux.

Currently, the host comes out of the box with Kubernetes installed. A goal however is to move to a containerized Kubernetes installation, to more easily support different versions on the same host, such as OpenShift v3. The Atomic Host also comes with several Kubernetes utilites such as etcd and flannel. Kubernetes currently uses Docker, an open source project for creating lightweight, portable, self-sufficient application containers.

The host system is managed via rpm-ostree, an open source tool for managing bootable, immutable, versioned filesystem trees from upstream RPM content. This and several other components are wrapped in the atomic command which provides a unified entrypoint.

The Project Atomic umbrella also encompasses other tools which are essential to immutable, container-based infrastructures, including:

  • Cockpit gives visibility into your hosts and your container cluster.
  • Many patches and extensions to Docker for better SELinux and systemd integration.
  • The Atomic Developer Bundle to make development of containerized applications easy.

There are many more tools and projects available within Project Atomic. We’re building the next-generation operating system, one component at a time.

How Can Project Atomic Help Me?

  • The traditional enterprise OS model with a single runtime environment controlled by the OS and shared by all applications does not meet the requirements of modern application-centric IT.
  • The complexity of the software stack, the amount of different stacks, and the speed of change have overwhelmed the ability of a single monolithic stack to deliver in a consistent way.
  • Developer/DevOps-led shops seek control over the runtime underneath their applications, without necessarily owning the entire stack.
  • VMs provide a means for separation among applications, but this model adds significant resource and management overhead.

Slimming down the host with the Atomic distribution limits the surface area and patch frequency for administrators. Docker containers offer developers and admins a clear path to delivering consistent and fully tested stacks from development to production. Containers secured with Linux namespaces, cGroups, and SELinux give isolation close to that of a VM, with much greater flexibility and efficiency. And simple, easy-to-use tools like Cockpit provide cross-cluster capabilities to deploy and manage applications.

Documentation Index