Kubernetes CNI plugin vs Kube-proxy

Before discussing the difference between the two components, let’s take a second to define the CNI,

What is the CNI ?

CNI (Container Network Interface),is a Cloud Native Computing Foundation project, consists of a specification and libraries for writing plugins to configure network interfaces in Linux containers, it concerns itself only with network connectivity of containers and removing allocated resources when the container is deleted.

that way any plugin provider know what should be configured to be supported.

Differences between Kube-proxy and CNI plugins

CNI (Container Network Interface) and kube-proxy are both important components of the Kubernetes networking stack, but they serve different functions.

The CNI plugin is responsible for providing network connectivity between containers and pods. It manages the IP addresses assigned to each pod and handles network traffic routing and isolation.

Kubernetes supports a variety of CNI plugins, each with its own set of features and capabilities. The CNI plugin is responsible for setting up the networking infrastructure on each node in the cluster and ensuring that pods can communicate with each other, regardless of where they are running.

An example of famous CNI plugins : Flannel, Calico, Weave Net…

On the other hand, kube-proxy is a network proxy and load balancer that runs on each node in the cluster. Its primary role is to manage the network connectivity between services and their associated pods. It sets up the necessary networking rules and routes traffic to the appropriate pods.

kube-proxy provides service discovery, load balancing, and IP masquerading functionality, which makes it a critical component of the Kubernetes networking stack.

In summary, while the CNI provides the network connectivity between containers and pods, kube-proxy provides the network connectivity between services and pods. Together, these two components form the foundation of the Kubernetes networking stack, enabling the reliable and scalable operation of applications and services running on the platform.

Hope this help.