Question

A platform engineer is building a new Kubernetes cluster and wants to run containers using containerd instead of a different runtime. They need to understand how the kubelet on each node actually launches and manages containers. Through which standardized interface does the kubelet communicate with the container runtime?

Accepted Answer

The Container Runtime Interface (CRI), a gRPC API the kubelet uses to instruct the runtime to pull images and manage container lifecycles

Answer

The Container Network Interface (CNI), which the kubelet calls directly to start and stop containers

Answer

The Kubernetes API server, which forwards container start commands from the kubelet to containerd

Answer

The Open Container Initiative (OCI) runtime spec, which the kubelet invokes as a REST endpoint on each node