The Kubernetes Container Runtime Interface (CRI) acts as the main
connection between the kubelet and the Container Runtime.Those runtimes have to
provide a gRPC server which has to fulfill a Kubernetes defined
Protocol Buffer interface.This API definition evolves over time, for
example when contributors add new features or fields are going to
become deprecated. In this blog post, I'd like to dive into the
functionality and history of three extraordinary Remote Procedure
Calls (RPCs), which are truly outstanding in terms of how they
work: