Hey,

I have now tried to debug the following issue for two full days but not have been able to find a solution: I installed Zammad without a problem on my server, the incoming traffic is routed with caddy to the docker zammad nginx container, which should handle the rest™ of the traffic mangement. The website loads without a problem, but no connection to the websocket server can be established. The websocket container itself does not log anything after startup, the last message is "INFO -- : Using the Redis back end for Zammad's web socket session store.. The zammad nginx container logs for each connection attempt upstream prematurely closed connection while reading response header from upstream, client: 172.27.0.1, server: _, request: "GET /ws HTTP/1.1", upstream: "http://172.27.0.7:6042/ws" followed by GET /ws HTTP/1.1" 502 150 "-". Any idea on what could be causing this issue or how to debug this? I definetly hit the boundary of what I know with this issue, which is quite frustrating because everything else works without a problem. I would also be down to write some documentation if my setup works.

Any help is highly appreciated, tysm!

All the best, Paul

Infos

Docker version: 25.0.2
Docker-compose version: 1.29.2
Operating system (Docker host): Ubuntu 22.04.3 LTS

Expected behavior

Websocket Connection being established sucessfully

Actual behavior

Steps to reproduce the behavior

Standard zammad installation via docker compose with caddy setup as ingress point and reverse proxy.

Current Caddy reverse proxy setup

fqdn {
    encode gzip
    header Strict-Transport-Security "max-age=31536000;"

    reverse_proxy http://127.0.0.1:4353 {
        # Caddy automatically upgrades connections to HTTP/2 where possible.
        # Set header directives equivalent to the Nginx configuration.
        header_up Host {host}
        header_up X-Real-IP {remote}
        header_up X-Forwarded-For {remote}
        header_up X-Forwarded-Port {server_port}
        header_up X-Forwarded-Proto {scheme}
        header_up Connection {>Connection}
        header_up Upgrade {>Upgrade}
    }

        @ws {
                header Connection *Upgrade*
                header Upgrade websocket
        }
   # WebSocket configuration
    reverse_proxy /ws http://127.0.0.1:4353 {
           header_up Upgrade {http.upgrade}
    header_up Connection "Upgrade"
    header_up CLIENT_IP {remote_host}
    header_up X-Forwarded-For {http.request.remote}
    }
   header @staticFiles Cache-Control "max-age=31536000, public"
}

zammad / zammad-docker-compose

Unable to connect to websocket with caddy as ingress #400

Infos

Expected behavior

Actual behavior

Steps to reproduce the behavior

Current Caddy reverse proxy setup