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.