Self-hosted RudderStack 404 on public URL: check DNS spelling, not the proxy

TL;DR

If a self-hosted RudderStack data plane returns 404 at its public URL, check DNS first: make sure the hostname actually resolves to the reverse proxy, because a subtly misspelled record looks exactly like a proxy or app misconfiguration.

Steps

1. If a self-hosted RudderStack data plane returns 404 at its public URL, check DNS first: make sure the hostname actually resolves to the reverse proxy, because a subtly misspelled record looks exactly like a proxy or app misconfiguration. Then sanity check the backend directly, bypassing the proxy, with a GET on /health (rudder-server serves no homepage at /, so 404 there tells you nothing). Only after DNS and direct access work should you debug Traefik router rules and the loadbalancer port (8080 by default).

When to use

You are seeing this: Then sanity check the backend directly, bypassing the proxy, with a GET on /health (rudder-server serves no homepage at /, so 404 there tells you nothing). Use this skill when you run into "Self-hosted RudderStack 404 on public URL: check DNS spelling, not the proxy".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: GitHub issue rudderlabs/rudder-server#6353 (closed, 13 comments): a self-hosted RudderStack on Docker behind Traefik returned 404 page not found on the public URL no matter what the reporter tried: isolated container, shared networks, double-checked Traefik config. Everything looked right. The actual cause was a one-character difference in the DNS record, so the hostname never reached Traefik at all, and the reporter confirmed it works after fixing the DNS.

Verified resolution: If a self-hosted RudderStack data plane returns 404 at its public URL, check DNS first: make sure the hostname actually resolves to the reverse proxy, because a subtly misspelled record looks exactly like a proxy or app misconfiguration. Then sanity check the backend directly, bypassing the proxy, with a GET on /health (rudder-server serves no homepage at /, so 404 there tells you nothing). Only after DNS and direct access work should you debug Traefik router rules and the loadbalancer port (8080 by default).

Source URL: https://github.com/rudderlabs/rudder-server/issues/6353