Containers still mean “Docker” to many people. Docker popularised the modern use of containers in software development and deployment. These days, other technologies are around too. Here’s how Containerd, Docker and Kubernetes relate to each other. By James Walker.
As Kubernetes grew and more third-party tools arose around Docker, the limitations of its architecture became clear. At the same time, the Open Container Initiative (OCI) began standardising container formats and runtimes. This resulted in an OCI specification defining a container which could be used by multiple runtimes, of which Docker is an example.
The article covers:
- The rise of containerd
- Understanding containerd’s role
- The OCI
- What about my Docker images?
- Kubernetes and Docker
Containerd drops in to abstract this low-level wiring. It’s intended as a “client layer” that container software then builds atop of. This might be developer-oriented software, like Docker, or cloud-oriented devops tools such as Kubernetes. Each high-level user-facing interface (such as Docker and Kubernetes) now benefits from a choice of interchangeable low-level container runtimes (like containerd and runC). Good read!
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