container x interface


container x interface

container interfaces

These days Kubernetes can be best described as an API driven interface to a distributed system, with in tree support for orchestrating containerized workloads. Following its big tent model of supporting a variety of vendors, it has broken out integrated support for container runtimes, storage and networking into interfaces that can be implemented by various solutions.


The Container Runtime Interface spec defines a gRPC service for kubelet to talk to to manage containers. While this is intended to be run per node, I don't think there's anything stopping you from actually running the containers elsewhere.


The Container Storage Interface spec follows a similar model, but with an optional controller component. This looks primarily usef to attach volumes to nodes, and then the runtime can mount it into a container.


The Container Networking Interface spec has a different model more like unix cli tools. Plugins are executed on a host to configure networking (namespaces) directly, and they can execute each other if necessary.