kubernetes - LoadBalancer如何将流量转发到目标服务？

Question

LoadBalancer是使用in this article提到的kube-proxy还是使用here提到的NodePort？

如果实际上使用的是NodePort，那么为什么像MetalLB这样的多个来源声称在生产中使用NodePort并不是一个好主意？
Ingress也可以使用NodePort + nginx进行操作。那么LoadBalancer有什么特别之处？

Answer 1

这取决于云提供商的实现:

Traffic from the external load balancer will be directed at the backend Pods, though exactly how that works depends on the cloud provider.

https://kubernetes.io/docs/concepts/services-networking/#loadbalancer

如果是Google Kubernetes Engine(GKE)，则 this is how it works:

When using the external load balancer, arriving traffic is initially routed to a node using a forwarding rule associated with the GCP network. After the traffic reaches the node, the node uses its iptables NAT table to choose a Pod. kube-proxy manages the iptables rules on the node.