Merge pull request #30606 from saschagrunert/cri-architecture

Add CRI architecture to cluster concepts

content/en/docs/reference/glossary/container-runtime-interface.md

@@ -0,0 +1,22 @@
+---
+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.
+
+<!--more-->
+
+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" >}}.