Using Traefik, how to expose inner HTTPS errors (like expired certs)?

Danya02

5/26/24, 9:56 PM

I'm using Traefik as a reverse proxy to my homelab. I'd like to use HTTPS inside the lab using a custom CA. To do this, I've set up a ServersTransport that trusts my lab CA.

This worked well until a few days ago when a critical service's certificate expired. At that time, Traefik returned a page saying "Internal Server Error" and nothing else, and I had to log in to the proxy server to discover that it was indeed a certificate expiring that caused it.

Is there a way to configure Traefik so that, when there is a TLS error, it would show what the error is? I can't use an Errors middleware because the inner services might return 500 errors as well, and I can't afford to lose access to the bodies of those responses like Errors would.

(I would accept having to switch to a different reverse proxy if it turns out that Traefik can't easily do it. It doesn't seem like many others can do anything like this.)

0 + 3

ssl

https

reverse-proxy

traefik

Ginnungagap

5/27/24, 6:11 AM

Would using the [Traefik dashboard](https://doc.traefik.io/traefik/operations/dashboard/) be a viable solution?

Danya02

5/27/24, 5:29 PM

@Ginnungagap How does that help? I tried to add a router with a service pointing at https://expired.badssl.com/, and that showed up with a status of "OK" on both. Maybe some kind of metrics needs to be enabled for such errors to show up?

Ginnungagap

5/28/24, 8:34 AM

You need an associated healthcheck for the service to be marked down.

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