Why does everyone use reverse proxies? It seems complex and inefficient. Why not serve xhr's and other dynamic content from the app server(s) and static content from a static webserver?
All of which could be done at the app server level sure, but then that would shift that complexity to your app and your developers.
Oh and job security, obviously.
Kubernetes runs a cluster of machines that act like a mini internet, with many containers running many apps. These apps communicate with each other across containers and machines through a series of proxies so that apps only have to worry about a single address or service name. Kubernetes does allow for headless services which will publish all of the pod IPs under a DNS name if you want but this is usually not the common scenario.
Beyond just knowing endpoints, apps may need to worry about healthchecking, failover, load balancing, rate limiting, security, observability, routing decisions and more. It's far simpler to consolidate all this functionality rather than leaving it to every single app to implement it all over again.
An ingress controller is in charge of running a specific proxy that deals with traffic into and out of the cluster rather than within it. There are several implementations other than nginx and they all require various levels of tuning to fit the needs of the cluster, but it's an optimal solution since you might not want or have access to control traffic on the other side.
Round-robin DNS might also work or complement this.
Almost everything on the internet is behind layers of proxies, it's not a bad thing and isn't much cause for concern.
It's a proven design rule (the end-to-end principle) to prefer the smarts at the edges of your system, and the problems stemming from the reverse proxy described in the article, in my book, counts as further evidence for this idea.
That's exactly what reverse proxies do - leaving the internal apps free to just serve requests instead of worrying about the perimeter.
The problems described in this article have nothing to do with reverse proxies but rather the ingress controller and config settings.
Technologies/competencies change as projects evolve, and being able to effortlessly reorganized and reroute is so profoundly powerful.