Documentation should clarify nginx ingress required

[larryclaman]

Describe the bug

The documentation needs to be clear and precise about which nginx ingress controller flagger works with. On the page docs/gitbook/tutorials/nginx-progressive-delivery.md, it talks about the "NGINX ingress controller", and the accompanying diagram also refers to (and uses the icon of) the NGINX ingress controller.

However, the examples later on the page reference the "ingress nginx" ingress controller, eg helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx

These are two different software products and it's confusing that both are referenced in the same document.

The ingress nginx ingress controller is maintained by the CNCF, and can be found at https://kubernetes.github.io/ingress-nginx/

The NGINX ingress ingress controller is maintained by NGINX Inc, and can be found at https://docs.nginx.com/nginx-ingress-controller/

Could the owner of this documentation please review and clarify?

To Reproduce

n/a

Expected behavior

Clarity on which ingress controller is supported

Additional context

N/A

[kingdonb]

The open source nginx, which is under Kubernetes and the CNCF, is the supported one.

The other nginx is not tested against Flagger and will not work AFAIK. We need a better way to make the distinction than "nginx ingress" vs "ingress nginx" because these are not clear for speakers of all languages, right now the best way to disambiguate them is from the Helm chart Repo URL, (which you have found the correct ingress-nginx through the doc.)

Thanks for the feedback. Will leave this open until we can make an effective distinction between them without calling out a commercial product in the docs, (I think that is what blocks progress on this issue, it has definitely come up before.)

[larryclaman]

Thanks for looking at this! (Obviously the larger problem is well beyond flagger; clearly the fact there are two ingress controllers with similar names 'ingress nginx' and 'nginx ingress' is confusing in any context.) Can't tell you how many times I've helped folks who were looking at the wrong set of documentation for one versus the other.