Kube-proxy is an important component of a Kubernetes system that enables it to route and access services inside the cluster. It is responsible for setting up routing tables for every Service, irrespective of whether it is a node port, cluster IP, or external load balancer. Kube-proxy works by monitoring the Kubernetes API server for new Services and Endpoints and then configuring network rules accordingly. It also maintains network connections between nodes and the Services they provide.
Kube-proxy runs on each node of the cluster and is responsible for listening to Kubernetes API server for service and endpoint changes, configuring iptables based on those changes, and forwarding requests to the right node and service. The kube-proxy listens to the API server and creates and synchronizes iptables rules with the service configuration named ‘iptables mode’ and ensures network traffic is routed correctly between nodes in the cluster. The kube-proxy uses the Linux kernel-level packet filtering and forwarding mechanism, iptables, to establish rules for forwarding packets. By default, kube-proxy uses the iptables mode, but can be configured to use ipvs mode, which is a layer-4 load balancing alternative.
In a nutshell, kube-proxy is the networking glue that binds nodes and services together, allowing them to communicate securely and reliably. Kube-proxy allows users to manage services and give them access to external clients and other pods. It is an important part of any Kubernetes cluster, ensuring reliable communication within and outside of the cluster.
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