FAQ

WHAT IS THE RELATIONSHIP BETWEEN CONTAINERD, OCI AND RUNC?

Docker donated the OCI specification to the Linux Foundation in 2015, along with a reference implementation called runc.

Containerd integrates OCI/runc into a feature-complete, production-ready core container runtime.

Runc is a component of containerd, the executor for containers.

Containerd has a wider scope than just executing containers: downloading container images, managing storage and network interfaces, calling runc with the right parameters to run containers.

Containerd fully leverages the Open Container Initiative’s (OCI) runtime, image format specifications and OCI reference implementation (runc) and will pursue OCI certification when it is available.

Because of its massive adoption, Containerd is the industry standard for implementing OCI.

总结：OCI规范包括runtime-spec、image-spec、distribution-spec等。Runc仅仅实现了runtime-spec规范，而Containerd实现了完整的规范——并且在实现runtime-spec时借助了Runc。