Kubernetes Contributor Summit North America 2024

Most users know a cluster exposes an HTTP/REST API; but interactively communicating with a container requires more performance than the typical HTTP request-response mechanism can provide. Which is why Kubernetes clusters also expose bidirectional streaming interfaces. This presentation dives deeply into the mechanics of the Kubernetes streaming interfaces. We will follow the streamed data as it traverses numerous components of the cluster from a client such as kubectl to the API Server, through a kubelet on a Node, through the Container Runtime Interface (CRI), all the way to the container runtime itself. We will finish by outlining the newest efforts to modernize the Kubernetes streaming protocol from the current aging SPDY to WebSockets (SIG API Machinery - KEP 4006).