Containerd (pronounced “container-D,” not “contain-nerd”) is the bare-bones software you would need to create a Docker container. You could think of it as a Docker container without the frills.
Today’s move is part of an ongoing effort to modularize the Docker platform, writes Docker Inc. founder Solomon Hykes in a blog posting. Containerd came into being last year as part of that effort and as a way to bring the Docker platform in line with the Open Container Intitative (OCI).
Containerd officially became part of the Docker platform with the release of Docker 1.11 in April.
As for why Docker wants to modularize, Hykes writes that it’s a case of simplification. The Docker platform has grown to include many tools related to infrastructure. For example, as of June, the platform includes Swarm, the Docker orchestration tool that’s an alternative to Kubernetes.
For developers, the stripped-down containerd is “a component that they can customize, extend, and swap out as needed, without unnecessary abstraction getting in their way,” Hykes writes.
Another way to interpret the move is that Docker can more freely ignore Docker’s choices for infrastructure and management. Swarm would be one example; containerd might help ease any friction that Kubernetes fans are feeling toward Docker Inc. about bundling Swarm into the platform.
In a prepared statement, CoreOS CTO Brandon Philips points out CoreOS’ role in getting OCI started and adds: “Giving users choice and flexibility with runtimes will help make it easy to take the next step to orchestrate containers with Kubernetes.” (The statement doesn’t mention Swarm.)
Philips also notes that it’s “great to see discussion on the container execution architecture today,” adding: “Ultimately we want distributed infrastructure to become the solid ‘boring’ plumbing so businesses can better focus on innovation with their applications.”
Containerd is in version 0.2.4. The 1.0 release — the first one deemed suitable for production use — is slated for the second quarter of 2017.