<p>I deploy an <code>nginx ingress controller</code> to my cluster. This provisions a load balancer in my cloud provider (assume AWS or GCE). However, all traffic inside the cluster is routed by the controller based on my ingress rules and annotations.</p>

<p>What is then the purpose of having a load balancer in the cloud sit in front of this controller? It seems like the controller is doing the actual load balancing anyway?</p>

<p>I would like to understand how to have it so that the cloud load balancer is actually routing traffic towards machines inside the cluster while still following all my <code>nginx</code> configurations/annotations or even if that is possible/makes sense.</p>

<p>You may have a High Availability (HA) Cluster with multiple masters, a Load Balancer is a easy and practical way to "enter" in your Kubernetes cluster, as your applications are supposed to be usable by your users (who are on a different net from your cluster).
So you need to have an entry point to your K8S cluster. </p>

<p>A LB is an easy configurable entrypoint.</p>

<p>Take a look at this picture as example:
<a href="https://i.stack.imgur.com/982Fk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/982Fk.png" alt="enter image description here"></a></p>

<p>Your API servers are load balanced. A call from outside your cluster will pass through the LB and will be manager by a API server. Only one master (the elected one) will be responsible to persist the status of the cluster in the etcd database. </p>

<p>When you have <code>ingress controller</code> and <code>ingress rules</code>, in my opinion it's easier to configure and manage them inside K8S, instead of writing them in the LB configuration file (and reload the configuration on each modification). </p>

<p>I suggest you to take a look at <a href="https://github.com/kelseyhightower/kubernetes-the-hard-way" rel="nofollow noreferrer">https://github.com/kelseyhightower/kubernetes-the-hard-way</a> and make the exercise inside it. It's a good way to understand the flow.</p>
