Nginx-Ingress

This draft captures a real troubleshooting pattern for 504 Gateway Timeout responses behind Kubernetes ingress by checking the ingress rule, backend service, pod health, and in-cluster connectivity from the ingress controller itself.

This draft turns a real cluster note into a cleaner walkthrough for installing cert-manager, configuring a Cloudflare-backed ClusterIssuer, issuing certificates, and handling a few common ingress-related surprises.