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rkt: The pod-native container engine launches in the CNCF

By: Jonathan Boulle, rkt project co-founder, CNCF TOC representative, and head of containers and Berlin site lead at CoreOS

Earlier this month, we announced that CoreOS made a proposal to add rkt, the pod-native container engine, as a new incubated project within the Cloud Native Computing Foundation (CNCF). Today we are happy to celebrate that rkt has been formally proposed and accepted into the CNCF.

This means that with rkt now housed in the CNCF, we ensure that the rkt and container community will continue to thrive in a neutral home for collaboration. We are excited to work alongside the CNCF community to push forward the conversation around container execution in a cloud native environment. We look forward to working alongside the CNCF to further the development of the rkt community and develop interoperability between Kubernetes, OCI and containerd.

It is a historical moment where CNCF has the opportunity to push progress on container execution for the future of the ecosystem, under a neutral and collaborative home. The future of container execution is important for cloud native. Rkt is now joining the CNCF family alongside other critical projects like gRPC, Kubernetes, Prometheus, and others.

Working with the community and next steps

rkt developers already actively collaborate on container specifications in the OCI project, and we are happy to collaborate more on the implementation side with the CNCF. We are actively working to integrate rkt with Kubernetes, the container cluster orchestration system, and together we can work to refine and solidify the shared API for how Kubernetes communicates with container runtimes. Having container engine developers work side-by-side on the testing and iteration of this API ensures a more robust solution beneficial for users in our communities.

The OCI project is hard at work on the standards side, and we expect we will be able to share the code in working with those image and runtime specifications. rkt closely tracks OCI development and has developers involved in the specification process. rkt features early implementation support for the formats with the intention of being fully compliant once the critical 1.0 milestone is reached.

What can rkt users expect from this new announcement? All of the rkt maintainers will continue working on the project as usual. Even more, we can encourage new users, and maintainers, with the help of the CNCF, to contribute to and rely on rkt.

We encourage the community to continue using rkt or try it out: and you can get involved on the rkt page on GitHub or on the mailing list.

A big thank you to all the supporters of rkt over the years. We would also like to thank Brian Grant of Google for being the official sponsor of proposal for rkt’s contribution into the CNCF.

FAQ

What is rkt? A pod-native container engine

rkt, an open source project, is an application container engine developed for modern production cloud-native environments. It features a pod-native approach, a pluggable execution environment, and a well-defined surface area that makes it ideal for integration with other systems.

The core execution unit of rkt is the *pod*, a collection of one or more applications executing in a shared context (rkt’s pods are synonymous with the concept in the Kubernetes orchestration system). rkt allows users to apply different configurations (like isolation parameters) at both pod-level and at the more granular per-application level. rkt’s architecture means that each pod executes directly in the classic Unix process model (i.e. there is no central daemon), in a self-contained, isolated environment. rkt implements a modern, open, standard container format, the App Container (appc) spec, but can also execute other container images, like those created with Docker.

Since its introduction by CoreOS in December 2014, the rkt project has greatly matured and is widely used. It is available for most major Linux distributions and every rkt release builds self-contained rpm/deb packages that users can install. These packages are also available as part of the Kubernetes repository to enable testing of the rkt + Kubernetes integration. rkt also plays a central role in how Google Container Image and CoreOS Container Linux run Kubernetes.

How were rkt and containerd contributed to the CNCF?

On March 15, 2017, at the CNCF TOC meeting, CoreOS and Docker made proposals to add rkt and containerd as new projects for inclusion in the CNCF. During the meeting, we as rkt co-founders, proposed rkt, and Michael Crosby, a containerd project lead and co-founder, proposed containerd. These proposals were the first step, and then the project went through a formal proposal to the TOC, and finally were called to a formal vote last week. Today these projects have been accepted to the organization.

What does this mean for rkt and other projects in the CNCF?

As part of the CNCF, we believe rkt will continue to advance and grow. The donation will ensure that there is ongoing shared ecosystem collaboration around the various projects, where interoperability is key. Finding a well-respected neutral home at the CNCF provides benefits to the entire community around fostering interoperability with OCI, Kubernetes, and containerd. There’s also an exciting number of opportunities for cross-collaboration with other projects like gRPC and Prometheus.

Container execution is a core part of cloud-native. By housing rkt under the CNCF, a neutral, respected home for projects, we see benefits including help with community building and engagement, and overall, fostering of interoperability with other cloud native projects like Kubernetes, OCI, and containerd.

How should we get involved?

The community is encouraged to keep using, or begin using rkt, and you can get involved on the rkt page on GitHub or on the mailing list. Note that this repo will be moved into a new vendor-neutral GitHub organisation over the coming weeks.