--- title: Container Runtime Interface id: container-runtime-interface date: 2021-11-24 full_link: /docs/concepts/architecture/cri short_description: > The main protocol for the communication between the kubelet and Container Runtime. aka: tags: - cri --- The main protocol for the communication between the kubelet and Container Runtime. The Kubernetes Container Runtime Interface (CRI) defines the main [gRPC](https://grpc.io) protocol for the communication between the [cluster components](/docs/concepts/overview/components/#node-components) {{< glossary_tooltip text="kubelet" term_id="kubelet" >}} and {{< glossary_tooltip text="container runtime" term_id="container-runtime" >}}.