<p>All the tutorials I've found on the Internet demonstrate how to deploy a web site/app in an nginx container and set up an Ingress to proxy related requests to that container.</p>
<p>That seems kind of redundant to me. Why not to place the content on a volume, mount it to ingress-nginx-controller and serve static assets from there. It seems to be better from performance perspective: no additional proxy and no additional container (with nginx) that consumes compute resources.</p>

<p>An <a href="https://kubernetes.io/docs/concepts/services-networking/ingress/" rel="nofollow noreferrer">Ingress</a> resource is an abstract concept that was designed to route HTTP/S requests to kubernetes services. It defines a limited subset of that functionality to remain generic and be implemented by many types of ingress controller.</p>
<p><a href="https://github.com/kubernetes/ingress-nginx" rel="nofollow noreferrer">ingress-nginx</a> is only one implementation of an ingress controller, that happens to also be good at serving static content. <a href="https://www.haproxy.com/documentation/kubernetes/latest/configuration/ingress/" rel="nofollow noreferrer">HAProxy</a>, <a href="https://doc.traefik.io/traefik/providers/kubernetes-crd/" rel="nofollow noreferrer">Traefik</a> or the <a href="https://github.com/kubernetes-sigs/aws-load-balancer-controller" rel="nofollow noreferrer">AWS lb</a> are at the other end of the scale.</p>
<p>An nginx based ingress controller could add custom <a href="https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/" rel="nofollow noreferrer">annotations</a> to support something custom like what you propose, but I imagine you would have a hard time arguing that into the project. Internally, they already add a second nginx instance for the default backend.</p>
<p>If one proxy hop is a critical differentiator in performance then you would probably get more benefit hosting the static content on an edge CDN/device. Another alternative is to not rely on an Ingress and publish the service directly to the outside world.</p>
