Kube-proxy主要负责Service的实现。
kube-proxy enables the Kubernetes service abstraction by maintaining network rules on the host and performing connection forwarding.
The Kubernetes network proxy runs on each node.
This reflects services as defined in the Kubernetes API on each node and can do simple TCP and UDP stream forwarding or round robin TCP and UDP forwarding across a set of backends.
Kube-proxy提供两种方式的LB: Iptables or IPVS
到1.11版本为止默认还是使用Iptables来实现，但是在1.11版本中IPVS已经更新为稳定版本。