The CNCF Technical Oversight Committee (TOC) has voted to accept Flatcar as a CNCF incubating project. Flatcar is a zero-touch, minimal operating system (OS) for containerized workloads, addressing the challenges of managing and securing a production fleet at scale. It is meant to be deployed the same way cloud native applications are deployed: by applying a declarative configuration, creating an immutable instance from a well-defined image.

“A secure community-owned cloud native operating system was one of the missing layers of the CNCF technology stack,” said Chris Aniszczyk, CTO of CNCF. “As validated by a thorough due diligence process, Flatcar has more than proven itself in this role, and we are thrilled to adopt it as an Incubating project and will support growing its community.”

Flatcar was originally created by the team at Kinvolk, a Berlin-based cloud native technology company that is now a part of Microsoft, as a derivative of CoreOS Container Linux. Flatcar is a popular base operating system for Kubernetes, and is closely integrated with Cluster API for streamlined deployments.

Main Features:

• Container Optimized: Flatcar’s OS image includes only those packages needed to run containers. This minimalist approach reduces the amount of software to manage, as well as the potential attack surface.
• Secure and Immutable File System: The OS is deployed to a cryptographically secured read-only filesystem which eliminates a whole category of security vulnerabilities that modify installed OS files.
• Declaratively Provisioned: Node configuration is defined in a YAML file which is applied on first boot. Thereafter, node configuration is generally treated as immutable, avoiding “configuration drift” and enabling management at scale.
• Auto Updating (and Rollback): Updates are shipped as validated images and applied in an atomic operation. If the update fails, then the system automatically reverts to the previous image. The project includes an update server that provides for advanced fleet-wide policy controls and graphical view of fleet status.

Flatcar has experienced significant success with end user adoption including by Adobe (SaaS provider, with more than 20,000 nodes running Flatcar), Stackit (managed Kubernetes service), and Wipro (managed PostgreSQL service).