32. Explanation of core components of Kubernetes——kube-proxy

This chapter explains the knowledge points

• 1. kube-proxy overview
• 2. working principle
• 3. Proxy mode of kube-proxy

---

1. kube-proxy overview

In order to support the horizontal expansion and high availability of the cluster, Kubernetes abstracts the concept of Service. Service is an abstraction of a set of Pods, and it will access this set of Pods according to access policies (such as load balancing policies).

Service provides a stable IP address and DNS name , which enables the service to be accessed by clients in these unified ways, and the service will forward the request to the backend Pod. In many cases, Service is just a concept, and what really implements the role of Service is the kube-proxy service process behind it. Only by understanding the principle and mechanism of kube-proxy, can we truly understand the implementation logic of Service. We have explained in detail the use of Service + kube-proxy + iptables to achieve load balancing in the Service chapter. This chapter will discuss the kube-proxy component again.

2. Working principle

Kube-proxy maintains network rules on nodes and implements part of the Kubernetes Service concept. Its role is to make the traffic sent to the Service (via ClusterIP and port) load balance to the correct backend Pod.

kube-proxy monitors the changes of resource objects in the API server,